INTERNATION
AL LAW
CHAPTER 1
1.International law, like any other, is the product of social and political progress; this means
that if society (represented by prevailing factions) is homogenous, then the legal process
will be smooth. This smoothness comes from the general acceptance of the legal rules
governing relations, accompanied by spontaneous compliance with the law.
International law can be seen either as a set of rules creating rights and obligations
combined with rules providing for an authoritative system, or as a thermometer of the state
of health on international society. Right now, the state of health is very poor, consequently
the fundamental rules are often abused, whilst the others are silently complied with.
Major powers harm the international order by pursuing their own ends causing one crisis
after another in time. This problem lies in the political division of nation-states and in the
polarization of cultural, social and political divisions.
In many nations, due to the lack of dialogue, competing attitudes and chasm between the
rich and the poor, there are disruptive social and political outcomes on the domestic level.
This inevitably reflects on the international scenery  underlined by louis Henkin who said
that the health of law depends on the health of society. The lack of multilateral cooperation
makes it impossible to pursue international peace and security; in fact, when law is
repeatedly misused, it's because of social and political decay.
Friedrich de Martens stressed how the flaws of international law are a consequence of the
instability characterizing the domestic legal system prevailed in all states.
There’s the fundamental rule on the prohibition of violence, but most people who act in
breach of the ban, resort to justifying their conduct by invoking self-defense or humanitarian
intervention  this makes it so that the disputes arising from this would be subject of
domestic litigation of a criminal law, where assessment of the disputed facts is key.
If a state acts against the recognized rule defending itself by appealing to justifications
contained within the rule, it is seen as a confirmation of the rule.
A reform design always remains a question, it first rose in the early 1990s after the collapse
of USSR. It then appeared clear that the legal and institutional adoption policy should consist
of faithful adherence to the design of the UN Charter  the want to make it stronger to
protect human rights, maintaining peace and making preventive diplomacy a priority.
The UN Security Council instituted the Secretary-General to produce a study on how to
overcome new threads to peace and security, that fell into their competence.
They came up with a system to implement the collective security legal framework, which
was never put in action due to veto power. This system under the Charter project was then
revived thanks to new engagement in international cooperation through multilateral
cooperation, thanks to which the veto wouldn’t have any power. The discussion now verted
around the power of those who decided the composition and functioning of international
institutions.
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2. Professor Shabtai Rosanne stated that an attorney cannot be fully qualified if they’re
unable to identify an international law element in a problem.
Domestic law attorneys should take into account the role of domestic courts and tribunals in
the application or violation of international law.
There has been an escalation of litigations involving sovereign parties that caused an
increase of legal representation of governments before international courts. This problem
must be followed by domestic lawyers through the impact of their clients  the
interdependence caused by this has added an international dimension to the work of
governmental administrations. A similar case is shown by NGOs (non-governmental
organizations) which promote the enforcement of international law in environmental and
human rights law. At the same time, corporations promote international standards in areas
addressed to corporate conduct.
3. International law consists of a set of rules made by states, and which belong to the
international legal order shared by every state (even if one may differ regarding the national
legal system). This body of law, found in every nation, has a guide for domestic judges to
decide which law to apply in a case that contains a foreign element  if there’s a connection
with more than one country, you need to know which law will govern; in fact, every national
legal system has connecting factors to simplify the work of the domestic judge. The
uncertainties and complications deriving from different laws, they adopted international
conventions on uniform domestic rules of private international law.
This legal system requires an interdisciplinary approach in the process consisting of
interactions which produce, use and apply rules.
The interstate nature of international law in apparent from diplomatic settings, where interstate agreements are entered into by state organs thanks to the international scope of
application of most rules of international law; in fact, most rules of international order are
implemented within the domestic legal orders.
4. Many international rules provide constraints to the recipient states regarding jurisdiction
to prescribe, adjudicate and enforce  for example there are rules about the treatment of
aliens or the treatment of foreign states and intergovernmental organizations, who have
higher standards than those appliable to private foreign individuals.
Environmental international rules require the passing of domestic legislation and
administrative conduct that state agencies must take in charge  these rules are
incorporated in domestic law and used in many fields.
International trade law in made up of obligations on barriers that require domestic regulatory
action; If this action, may this be either regulatory or administrative, is in contrast with
international standards, then they may redress to the local judiciary, which then mends the
conduct inconsistent with obligations by other state organs.
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5. Usually, international legal obligations are made as a mirror of the rights produced by
reciprocity  states make self-constraints in exchange for advantages deriving from this
reciprocity. This mechanism is called synallagmatic (bilateral obligations) and it reflects
traditional civil law that has been followed until the 17th century.
After Second World War a new set of rules towards states has been made with obligations
erga omnes  born from several obligations which made states abstain from treating foreign
nationals below a certain standard, upon the condition that the same treatment is accorded
to their nationals abroad.
6. States exercise their rights under international law, but also comply silently without being
noticed by the public  rules are here made under the “duty” aspect, rather than the “right”
side (which should lie under their utilitarian motives) and it’s here that the effectiveness is
questioned by people. The compliance with rules by states is spontaneous and it doesn’t
come from the fear of sanctions.
International legal rules have both a rights-based and a duty-based aspect. When states
negotiate and adopt treaties, they focus on securing rights for themselves and their citizens.
However, when it comes time to implement these rules, different government bodies must
handle the obligations that come with them.
As international law expands into areas once considered domestic matters, more
government ministries are now involved in enforcing international rules. This requires
coordination, which is often difficult to achieve.
Many international obligations are scientifically complex and financially burdensome,
making full compliance challenging. As a result, states may unintentionally violate
international law. This is particularly common in environmental law, where multilateral
agreements (MEAs) use flexible non-compliance mechanisms rather than strict
punishments to address violations.
More broadly, states may break international law when their self-interest conflicts with their
legal obligations. When this happens, they may either misinterpret the rule or justify their
actions by claiming a legal exception.
One last reason states might violate international law is to push for a change in the rules.
However, if this illegal behavior becomes widespread, it may prevent that change from
happening.
States must ensure their domestic courts avoid handling cases against foreign governments
when the issue involves governmental actions (acta iure imperii), but courts can rule on
commercial activities (acta iure gestionis) by foreign states.
This shift in the rule on jurisdictional immunity was followed by a similar change in immunity
from enforcement, which now protects only state-owned assets used for government
purposes. This gradual change, driven mainly by Western courts, faced opposition from
former Soviet countries and China, which saw it as violating international law. However,
China adopted this more limited immunity approach by passing a law in 2024.
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7. Over the years, the UN Charter has been an important factor making up the constitutional
process of international society that still lives  not completely representative because the
founding principles of contemporary international law dates earlier than 1945. Though, the
fact that rules are unwritten isn’t a sufficient argument to deny the existence of international
constitution.
Every society needs basic rules that define how people and institutions interact. These rules
establish fundamental rights — protections and freedoms that individuals and groups rely
on to live and participate in society. Without such rights, the society’s structure would
weaken, and its members would lack security and fairness.
These basic rules also outline how new laws are created and how existing ones might
change. This ensures that the society can adapt over time, responding to new challenges
or evolving values. They also shape the distribution of power. They determine who holds
authority, how decisions are made, and who gets to participate in that decision-making
process.
Ultimately, these rules serve a dual purpose: they protect the essential rights of individuals
and groups, while also structuring the society’s power dynamics to maintain order and
govern how change happens. It seems that for centuries, sovereign states have been the
principle to structure the international society, which has a low level of institutionalization
thanks to the groundnorm  it accounts for the lack of centralized forms of law-making,
adjudication and enforcement in international law.
The principle of sovereign equality has determined a horizontal dimension of modern society
characterized by bilateral relations  three main functions:
(a) consensual and participatory way of making rules.
(b) consensual dispute settlement with relevance of self-assessment of legality.
(c) self-help in the law-enforcement process.
Sovereignty serves both as a structural principle and a legal concept. Structurally, it ensures
states are equal, reinforcing their independence. Legally, it upholds political autonomy while
allowing states to participate in international law, like treaties and customary law, which
impose certain limitations. This balance fosters cooperation on issues like trade, security,
and the environment.
Sovereignty and international law are complementary, not conflicting. As Oscar Schachter
notes: “sovereignty is not absolute because international law, shaped by states, limits it”.
For example, states cannot invade others or violate human rights treaties.
The principle of non-intervention prohibits interference in internal affairs but doesn't stop
states from cooperating economically or culturally. International law creates a framework
that limits freedom in exchange for stability and cooperation, allowing sovereignty to adapt
to a more interconnected world.
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By the 17th century no one managed to prevail over others; adding the 1648 Peace of
Westphalia, it has been created a horizontal setting based on formal equality, independence
and competitive freedom  it allowed stronger states to prevail.
This context allowed for revolutionary attempts to reverse the system into a hegemonic one.
After the IIWW the process of self-reduction of state sovereignty has been accelerated
through the creation of international institutions and by multiplying international rules.
Talking about organizations, they don’t involve transfers of state sovereignty since members
still exercise elements of foreign policy; the acts are per se not legally binding (even if they
have binding measures); finally, Member states may still exercise their sovereignty to the
full extent of quitting the organization.
On the substantive law side, there have been constitutional changes and a shift in the
normative quality of obligations  from co-existence to cooperation. It provides legal
protection to general interests of the community of states  rules that provide erga omnes
obligations.
Peremptory norms  international rules that do not permit derogations. If a treaty is in
contrast with such rules, it will be considered null and void.
Such rules have been the result of the exercise of the external sovereignty of the generality
of nation-states during the negotiations that have led to the Vienna Convention on the Law
of Treaties.
After World War II, the world entered a period of social, economic, and ethical growth. This
encouraged countries to cooperate more, leading to the internationalization of national
policies and a shift toward multilateralism — even though Cold War tensions remained
strong. The push to defeat totalitarian regimes in the Soviet bloc and dismantle colonialism
played a major role in driving this trend forward. Additionally, global movements for human
rights, combined with the recognition of principles like self-determination, the ban on using
force against other nations’ territorial and the importance of respecting political
independence. These principles contributed to a broader sense of commitment to
international law.
The end of the Cold War in 1989, marked by the collapse of the Soviet Union and the fall of
communist regimes across Eastern Europe, brought a sense of global transformation. Many
countries began transitioning toward constitutional governments and free-market
economies. This period felt like a high point for international cooperation and multilateralism.
Additionally, the five permanent members of the United Nations Security Council (the US,
UK, France, China, and Russia) found themselves in strategic-military alignment.
However, this hopeful period was short-lived. A range of political developments and
emerging conflicts soon disrupted the sense of global unity and progress, marking the end
of this brief era of international harmony.  Notable failures of UN peacekeeping operations,
along with rising tensions between NATO and Russia over the former Yugoslavia,
highlighted challenges to international cooperation. This environment has fueled nationalism
and the rise of “sovereigntist” movements. However, emerging powers, have shown
openness to multilateralism, so while history moves in cycles, progress continues.
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8. The international legal order lacks three main functions: law-making, law-assessment and
law-enforcement. Also, there’s no parliamentary authority that legislates members nor any
compulsory adjudication like in domestic civil law. As a principle there’s no centralized police
that enforces international law or judgments over states, unless it is entrusted to an
international body by the state concerned  UN Security Council entrusted by state parties
to the UN Charter (constituent treaty of the UN).
In domestic legal systems, the effectiveness of the law is not superior to that of international
law  there’s a major structural difference with respect to the domestic means of lawmaking.
The challenges of international law compared to domestic legal systems are discussed, with
the suggestion that involving those affected by the laws in international law-making could
increase voluntary compliance.
International adjudication, like domestic litigation, can be slow and unpredictable, leading to
many disputes remaining unresolved or being settled privately. Even within domestic legal
systems, many important laws, such as those against murder or organized crime, are not
always enforced, yet this does not justify abandoning these legal systems entirely.
Legal systems, whether domestic or international, aim to establish ideal standards of
behavior, even though they are not always followed in practice.
Costumery law and general principles of international law may be indeterminate due to their
unwritten nature. The same can be said for treaties because, even though they are written,
they represent the compromised that follows diplomatic and political negotiations. As for
costumery law, it isn’t more contested than domestic law. Judge Crawford says that all
lawyers should know that is indeterminate  certainty and predictability are not constituent
elements of a legal system.
The aim is to maximize the predictability in social interactions, which is supported by
adjudication and enforcement  goal-oriented nature of law.
A contract is made to enhance the predictability that the terms agreed upon will be
respected.
9. International law is the expression of the social and political process from which it stems.
The shortcomings in the effectiveness of international rules are the result of the
contemporary social and political oscillations, particularly for those regarding the support for
the rule of law within nation-states.
International law stood out during the Cold war as a common language with which to argue
about the interpretation and application of old rules in the making of new ones. The feeling
of having one common language was shared by those wanted to change the rules and those
who wanted to keep them as they were  compromise formulas to reinforce reliance.
Regarding the North-South level, the UN general Assembly provided a forum in which
countries promoted the introduction of a new international economic order and at the same
time rules were consolidated through negotiations. Right now, the balance instituted during
cold war is threatened by the sense of diminished importance of cultural values.
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CHAPTER 2
1.Legal orders provide the rules that designate the subjects of law; these are both
recognized by and the addresses of the law, while having legal capacity to transfer rights,
duties and powers.
Legal subjects are also entitled to invoke the responsibility of other subjects when their rights
are violated, which means that they can demand that the violating party stops its actions. At
the same time legal subjects must comply with international legal obligations; if they breach
these obligations, they incur international responsibility  may lead to consequences.
In domestic jurisdictions the attribution of legal personality to both natural persons and
juristic persons, is strictly regulated. A legal subject is entitled to lodge claims and may incur
liability, which means that they can sue and be sued in front of a domestic court.
In international law, states are traditional legal subjects, followed by intergovernmental
organizations.
The lack of international centralization affects its legal process showing its high relativism
regarding the determination of legal personality of different entities. This is made complex if
we consider non-state actors, whose legal standing is more context dependent.
Entities recognized as international legal subjects also possess legal personality under
domestic law of the countries where they operate  domestic activities are governed by the
national laws. International law sets overarching standards that regulate how these entities
are treated. Headquarters agreements outline key provisions, protecting them from certain
legal and financial obligations under domestic law, ensuring independence and effective
functioning.
2. International legal order shows that states are social aggregates capable of exercising
their internal sovereignty: their jurisdiction to prescribe, to adjudicate and to enforce. This
also applies to the exercise of external sovereignty (freedom to make foreign policy).
International constraints may apply to states sovereignty; for example, in domestic
sovereignty, they have the duty to treat aliens in a non-discriminatory way.
Such constraints are mostly undertaken by states through the exercise of their sovereignty,
that is by entering freely the agreements or by producing costumery law through conduct of
domestic state organs. Governments decide whether to join treaties based on a cost-benefit
analysis, balancing political and economic interests.
By having the capacity to produce international law, states are also considered the bearers
of the rights and duties which flow from it. This legal capacity is subject to capacity under
the principles of effectiveness  the three legal requirements for acquiring international
legal personality coincide with the conditions of effective independent statehood
(government, territory and population). These elements suggest that any entity meeting
these requirements should be recognized as a state; however, there is no central
international authority to grant legal personality or certify the validity of a new state’s
existence.
This leaves the determination of statehood to the recognition by pre-existing states; this
carries significant political weight creating the appearance of an arbitrary process where
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certain entities gain recognition while others do not. This introduces political relativism 
recognition becomes about acceptance.
Most new states result from the transformation of a pre-existing state or states. These
transformations take different legal forms, including dismemberment (where a state breaks
into multiple new states), secession (where part of a state breaks away to form a new state
while the original continues to exist), and annexation (where a state absorbs the territory of
another). Annexation, however, typically results in the expansion of the annexing state’s
territory. When annexation happens through unlawful military force, states are generally
obligated not to recognize it as legitimate. This creates a tension between the principle of
non-recognition (upholding legal norms) and effectivity (the reality of who controls the
territory).
The tension between an entity’s objective fulfillment of legal criteria and the role of
recognition by existing states introduces uncertainty, which reflects the legal realities of state
creation and the political maneuvering that often determines whether a new state is
embraced by the international community or left in diplomatic limbo.
A requirement for the acquisition of international personality is the recognition as a state by
a pre-existing one  reflection of the constitutive recognition doctrine. However, under
international customary law, this doctrine is not valid; as observed during a case, the
recognition is nothing else than a declaration of existence, so is merely declaratory.
The admission to the UN as a member state can be taken as an indicator of statehood,
though this is not to be confused with a formal recognition. This admission would be relevant
only for the purposes of assessing its existence by the members that have voted in favor of
the request.
Article 4 of the UN Charter say that the state must prove to be a peace-loving country 
when voting, the already members only must take into consideration if the applicant meets
the criteria for admission. It’s impossible for international law to set a fixed number of
recognitions that would automatically make a new state legally valid for everyone. There’s
no established practice or legal belief (opinio juris) supporting such a rule, and it’s unlikely
that one will develop. However, getting recognition from many states can still provide political
and economic support, which helps maintain control. Without enough recognition, a new
state might struggle to survive — especially in today’s interconnected world.
The idea that recognition is declaratory (acknowledging a state’s existence rather than
creating it) has practical benefits. It lets existing states base their decisions on political
interests without legally committing to those choices. It also allows domestic courts and
authorities in non-recognizing states to still accept legal documents from the unrecognized
state, helping people avoid legal complications.
The EC Member states recognize new states upon the condition that they do not use
aggression, they comply inter alia with the principles of territorial integrity. The Badinter
Commission states that recognition is of a purely declaratory nature; therefore, the
Declaration is nothing more than what is meant to be.
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3.Starting from the 20th century, states felt the need to enhance their cooperation
internationally through permanent intergovernmental organizations, which have been
endowed with organs whose functions were primarily inward oriented. For example, taking
the UN, its general assemble and Security Council, provide negotiating fora for its member
states within the framework of its founding treaty. These organizations, often undertake
activities in which they appear to act on behalf of a separate legal subject (Status of Forces
Agreements). Generally, their treaties don’t contain previsions about the legal personality
and capacity of the organization in question.
Until the mid-20th century, international law recognized only states as having legal personality. So, when a UN
official was killed during a 1948 peacekeeping mission in Palestine, it was unclear whether the UN or Sweden
(the victim’s home country) had the right to hold Israel accountable and seek compensation. This uncertainty
led the UN General Assembly to request an opinion from the International Court of Justice (ICJ). It began by
stating that legal entities in any system don’t all have the same rights or roles — their status depends on the
needs of the international community.
The Court adopted a “functional” approach, focusing on whether the UN needed legal personality to carry out
its responsibilities. The ICJ concluded that, because the UN was tasked with maintaining peace and security,
it must have the legal capacity to bring claims for injuries to its staff.
The Court determined that the UN’s member states had implicitly given it legal personality because it was
necessary for the UN to carry out its assigned duties effectively even though this wasn’t explicitly stated in its
founding documents.
It was introduced a gradual concept of legal personality, recognizing that the UN’s legal
status is limited to what’s needed for it to perform its functions. However, their legal capacity
is limited to what’s essential for carrying out their specific tasks. This includes the ability to:
- Make international agreements
- Receive rights and duties from those agreements
- Be held responsible (and hold others responsible) for breaches of such agreements
This ensures organizations like the UN can function independently on the international stage
while staying within the bounds of their roles.
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4. Until the mid-1900s, individuals in international law were relevant only because they were
nationals of a given state while established in a foreign country, which meant being protected
under international costumery rules on the treatment of aliens.
The absolute freedom of treatment of their nationals and residents by a state was considered
a corollary to a principle of sovereign equality and independence  falls into domestic
jurisdiction. The latter is considered no longer legally effective, whereby states are supposed
to be internationally accountable for the treatment of any individuals outside their nationality.
When individuals receive treatment by the ghost country which is considered in breach of
international standards, they should resort to local remedies; after having exhausted them,
they could exercise diplomatic protection in their favor by their state  it consists of the state
bringing up the claim for the alleged unjust treatment vis-à-vis with the state where the
accident occurred. If both states have consented to international arbitration, the claimant
state may submit a settlement to the ICJ.
The problem is that this protection is based on utilitarian considerations according to their
foreign policy, which is connected to the fact that the recipients of the rights deriving from
international rules are not private individuals, but the states of nationality.
The formation of human rights law has pierced the veil of domestic jurisdiction reducing the
shield of national sovereignty against international scrutiny  not in contradiction with the
principle of sovereign equality since the constraints have been produced by states
themselves.
It has been developed a system of dispute settlement for the protection of foreign district
investment made through multilateral treaties. Under this treaties, foreign investors can
directly sue before an international tribunal, the state where the investment was made.
As to international human rights law, they benefit individuals, irrespective of their nationality
and these rights are often complemented by procedural rights directly addressed to
individuals. This also applies to foreign investors in relation to their substantive rights and
the right to sue states before the international arbitration tribunals.
Those developments have raised the question, also by developments concerning the
evolution of international criminal law, as to whether this doesn’t entail also affording
individuals with international legal personality. Answering it wouldn’t affect the actual rights
and duties created for them by states  these obligations can take two forms:
- they may be owed to other states that are parties to the same treaty;
- they may extend it to the whole international community.
When one seeks justice for human rights violations through international bodies, they act as
representatives of all the states that took part to the treaty. Often international law relies on
national systems to implement international commitments; in fact, many goals of
international law are achieved at the domestic level  particularly shown in human rights
where states bear a tridimensional duty: respect, protect and fulfill.
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In liberal democracies, civil society, organized through Non-governmental Organizations,
participates in the process of the pursue of the public good on the political and administrative
level under domestic guarantees.
Over the years, the increasing international relevance of various domestic factors has made
possible to develop NGOs, which are engaged in cross-border activities and have expertise
in specific areas that they operate in. They have legal personality only under domestic law,
so they cannot hold a state, nor themselves, internationally responsible. However, thanks to
their expertise, NGOs are now being formally admitted in international negotiations and lawmaking, where they can discuss but not vote.
The procedural institution called amici curiae in being referred to by international
adjudicative bodies according to which NGOs may submit briefs which may affect the
interest of the public.
Since 1996, the UN’s Economic and Social Council (ECOSOC) has allowed NGOs to
participate in UN activities. Qualified NGOs in economic, social, and cultural fields can
access preparatory documents, propose agenda items, and participate with observer status
— meaning they can make oral and written statements that may influence debates and draft
texts. If a country objects to an NGO’s participation, it has the right to respond. The UN
Secretariat can still approve the NGO’s involvement if the response is convincing.
NGOs have played important roles in international negotiations. For example, No Peace
Without Justice was active in the 1998 Rome Statute negotiations, training legal experts
who supported government delegations.
Governments often struggle to manage a wide range of complex issues during international
negotiations. In contrast, NGOs typically focus on specific topics, making them highly
knowledgeable  they frequently influence the final wording of international agreements.
NGOs also apply pressure on both national and international decision-makers, often pushing
for global public interests over short-term national goals. While many contribute
constructively, questions about their impartiality and funding have led to calls for stricter
transparency standards.
Public-interest NGOs  concerned only with the promotion of the public interest.
In the 2000 the UN Secretary General introduced the Global Compact initiative to promote
the voluntary adherence to universal principles by corporations in their business conduct.
Corporate Social Responsibility (CSR) refers to companies voluntarily following ethical
standards, especially in human rights, environmental protection, and health. Although these
standards aren’t legally required, they are becoming more widespread and aligned with
international laws.
Whether corporations are recognized as having international legal status doesn’t change
their accountability for breaking these standards. Even without an international court,
domestic courts are expected to enforce these international rules. This is especially
important for human rights, where states must not only avoid violating rights themselves but
also protect people from abuses by companies and individuals within their jurisdiction.
CHAPTER 3
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1.For legal rules to make up a legal order these must be some sources recognized in society
as capable to bring up such rules. This recognition makes facts, statements or documents
authoritative pieces of law.
The rules are about who and how to produce the rules addressed to the subjects of a legal
order; they are of a constitutional nature, and they define each legal order.
Given the principles of sovereign equality and independence of states, the ways by which
international legal rules are produced, is different from the ones used in domestic jurisdiction.
The main feature lies in their participatory nature  they are produced by the will of states
when associated with the conviction that such attitude conforms to what ought to be the law.
This principle is epitomized by agreements and custom.
In municipal legal systems there are two main approaches to the sources of law, differencing
from common law and civil law system:
- Common law jurisdiction: the authority of the law is looked for in jurisprudential
precedents of the same or higher courts, while lower courts are bound to follow the
decisions of the higher ones  stare decisis principle.
- Civil law jurisdiction: law is found in civil and penal codes and statutes. Prior decisions
are not binding but they have persuasive authority to the jurisprudence constante
doctrine. Judgments in civil law merely interpret and apply legislation.
Statutory law-making by a legislative body was introduced in some countries to pursue
clarity and precision which cannot be found in unwritten costumery law. Also, this way law
is much easily changeable to meet the needs for social change.
Additionally, national societies are evolving in more diversified fashions. Until a few years
ago, the common values in any national society were easy for domestic judges to apply on
a case-by-case basis. This law-making function is met with the acknowledgement of its
authoritative nature to the extent that is difficult to be found in conflictual societies.
Law-making in domestic jurisdictions in slow and difficult, and this reflects on the fact that
legislative process is frequently long.
Long negotiations produce statutes that represent a compromise between different views,
therefore is difficult to avoid subjective interpretation; this produces new complementary
legislations which may not provide clarity while introducing new problems in the already
existing legislation. Eventually this ends up with the judiciary.
These cases where we are confronted with unclear legislation there is an inevitable trend
towards creative jurisprudence.
In international law these interpretations are often left to self-interpretation by states, which
explains the importance of the linguistics of international law as a means of communication
among the different social and political components. Agreements, not only produce disputes,
but also settle disputes and makes them avoidable.
There is one component that differentiates international law from municipal legal systems,
and it concerns the absence of an institutional legislator in international law  flows from the
decentralized and scarcely institutionalized nature of international society of states which
derives from the sovereign equality.
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The UN General Assembly is a permanent organ composed of all the states of the
international community who are also UN Member states, which express their views of all
areas that cover the whole spectrum governed by international law. The debates that appear
often result in the adoption of General Assembly resolution cannot be compared to
parliamentary legislation because they have a hortatory effect so they cannot be sources of
law.
They also do not coincide with custom or agreements; the argument may produce instant
custom as an expression of opinio juris by states.
General Assembly resolutions do not create legally binding treaties, even if all member
states vote in favor. While state consent is essential for international agreements, delegates
voting on resolutions are only authorized to adopt non-binding instruments under the UN
Charter.
Legal practice and case law confirm that General Assembly resolutions are never treated as
treaties.
However, these resolutions can help shape new customary international law by providing
evidence of states’ legal beliefs (opinio juris).
The General Assembly aims at encouraging the progressive development of international
law and its codification. This has been pursued through the international law Commission
(34 persons elected by the General Assembly as independent experts). This is one of the
most influential bodies in the law-making process.
They are invested in codification conventions which consist of soft-law instruments raging
from simple draft articles to model rules. They are usually relied upon in diplomatic notes or
before courts. Their authoritative character comes from the research of states and
international practice in the works of the ILC; these are the outcome of the exchanges in
state representatives in the Sixth Committee of the General Assembly.
The International Law Commission has played a key role in shaping international law by
codifying complex issues over time. It has worked on topics like the most-favored-nation
clause, jurisdictional immunities, diplomatic protection, and transboundary environmental
damage.
In recent years, its focus has expanded to areas like environmental law and procedural law,
while still addressing fundamental legal principles like jus cogens and general principles of
law.
However, the UN General Assembly does not function like a legislative body in domestic
law. It is not authorized by the UN Charter to pass binding laws. Instead, its role is to facilitate
the development of customary and treaty law, which remain under the control of states.
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2. The sources of international law are usually those listed in the Article 38 of the Statute of
the international court of justice.
It reflects the shift from a natural law approach to a more positivist, consent-based legal
framework that dominated international law. This shift is evident in the way treaty law is listed
first among the sources of international law, highlighting the primacy of explicit state consent.
Furthermore, this consent-based approach is reinforced by the wording used: treaty law
must be “expressly recognized,” customary international law must be “accepted as law,” and
general principles must be “recognized” by states.
However, while all three categories require a form of state consent, its nature differs. The
explicit recognition required for treaties is not the same as the acceptance of customary
international law or the recognition of general principles. These distinctions reflect the
different ways in which international legal norms emerge and gain authority.
Although Article 38(1) presents the sources of international law in a simple way, its flexible
wording has allowed international courts and tribunals to interpret and adapt it over time.
Since its adoption, international practice has significantly refined the understanding of how
treaties are formed, how customary law develops, and how general principles of law are
identified. This evolution has provided greater clarity and precision in defining the processes
that give rise to binding international legal norms.
3. In international agreements, issues are relevant also for domestic attorneys and
operators. When domestic law implements international agreements, they will be interpreted
and applied at the same domestic level according to the assessment of the issues.
Under the pacta sunt servanda principle, international agreements produce rights and
obligations for the legal parties.
This principle is articulated through a set of rules that make up the body of treaty law codified
in the VCLT. It governs validity, duration and scope of application of international written
agreements. It may be labelled as a convention, treaty or otherwise, but its name doesn’t
bear normative consequences.
An international agreement consists of an expression of consent by a minimum of two
international legal subjects over the regulation of the subject-matter which constitutes the
scope of the agreement.
International case law has taken a broad approach to defining international agreements,
focusing on the commitments made rather than the form or label of the document.
In Jatar v. Bahrain (1994), Bahrain argued that meeting minutes were only a political understanding, not a
binding agreement. However, the International Court of Justice (ICJ) ruled that the minutes listed commitments
accepted by both parties, creating rights and obligations under international law. The ICJ also noted that the
lack of parliamentary ratification did not change this.
In the Bolivia v. Chile (2018) case, Bolivia claimed Chile was obligated to negotiate access to the Pacific Ocean.
The ICJ disagreed, stating that the documents Bolivia relied on did not outline commitments or mutual
obligations. One document even explicitly stated it did not create rights or obligations. Another, while politically
significant, was not directed at Bolivia and did not confirm any obligation to negotiate.
This highlights the distinction between international agreements and unilateral declarations.
The ICJ has ruled that for a promise to create legal obligations, the other party must accept
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it. However, when a state makes a clear public commitment about its future conduct, the ICJ
has recognized this as legally binding, even without the consent of other parties.
The good faith principle, combined with the forclusion, may provide the unilateral creation of
obligations for oneself but not for others.
The consensual factor brings to the subjective scope of the agreements. It doesn’t create
obligations or rights for a third state without its consent, which must be expressed in the
form of acceptance. Conversely, such consent is considered as presumed when a treaty
purports to afford rights to third states. Under the principle of good faith, these rights may be
exercised with the conditions provided in the treaty.
Until the 20th century, custom was the main source of international law, based on the
principle of freedom and competition. Treaty law was secondary to that and consisted in
bilateral treaties which would supplement customary law.
The decline of customary law became more pronounced after World War I, as divisions
within the international community deepened. The collapse of the Great European Powers
of the 19th century, the emergence of the Soviet Union in 1917, and the rise of populist
dictatorships in Europe contributed to ideological shifts. These developments led to World
War II, which introduced political and ideological divisions. At the same time, the process of
decolonization created further tensions between newly independent nations and
industrialized countries, especially in relation to economic governance and international
trade.
As these divisions intensified, the traditional values upheld through customary law at the
interstate level began to erode. In response, states sought to replace or modify customary
law through treaties.
This shift led to a growing reliance on treaty law to accommodate the evolving global order
and address newly recognized political and economic concerns.
Following World War II, the international legal framework expanded beyond bilateral
agreements, which primarily protected individual state interests on a reciprocal basis.
Instead, new multilateral treaties emerged to address broader regional and global issues.
This period saw the creation of major intergovernmental organizations, which played a key
role in shaping international law and governance.
Despite the persistent divisions between East and West, as well as between industrialized
and developing nations, extensive diplomatic efforts were made to renegotiate key aspects
of international law.  adoption of major codification conventions, which sought to redefine
and modernize fundamental legal principles to reflect the changing global landscape.
Through these developments, treaty law gradually took precedence over customary law as
the primary source of international legal regulation.
Some conventions protect collective interests, key examples include the two 1966
International Covenants on Human Rights as well as the 2015 Paris Agreement under the
1992 UN Framework Convention on Climate Change. Human rights treaties impose
obligations on all parties, allowing individuals to claim rights under them.
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Multilateral Environmental Agreements (MEAs) often create traditional bilateral
obligations for transboundary issues and broader duties to protect collective interests.
These obligations apply erga omnes partes, meaning they are owed to all states in the
agreement.
Bilateral treaties remain crucial in areas such as investment protection. Some multilateral
treaties even require additional agreements to implement general standards.
Treaties are written agreements governed by the VCLT, which is regarded in international
state practice and case-law to reflect the international costumery law.
Treaties are the end-product of negotiations conducted by governmental delegates and
states officials from the Ministries, which are competent in the subject-matter; also, their
officials often head state delegations.
Multilateral negotiations are more complex since they take place between a few states
and in ad hoc context or under the auspices of a global international organization. The
selected officials conduct the negotiations starting from the proposals on the agenda. The
final stage requires the unanimity of the states for the adoption of the text.
Article 9(2) refers to the adoption of the text in an international conference requiring the vote
of the two thirds. Nowadays, they decide by the so-called consensus.
A treaty is a source of international rights and obligations only upon its entry into force and
only for the states for which it entered into force. The adoption is valid only when the
negotiations are closed, so that the text can no longer be changed.
The VCLT leaves states free to choose which way they want to express their consent:
- Signature: indicates that a state agrees and intends to proceed in expressing its
consent. Although, in most cases, the signature alone doesn’t create binding legal
obligations.
- Ratification: is more formal, and it’s when a state expresses its consent to be legally
bound by the treaty. It usually involves domestic approval mechanisms. The state
submits the ratification to the treaty’s depositary.
- Accession: the state didn’t participate in the negotiation, or in the initial signing, but
becomes a party to it by submitting an instrument of accession.
The VCLT adopts a descriptive rather than prescriptive approach to the way states express their
consent to be bound by treaties. This was a deliberate decision during the negotiations in Vienna,
influenced by newly independent states, which opposed a rigid international rule on consent,
fearing it could legitimize unequal treaties—imposed on weaker nations by more powerful ones.
They also sought to preserve their sovereignty by ensuring that international law did not interfere
with their constitutional processes regarding treaty-making.
Articles 11-15 of the VCLT grant states full freedom to determine their own procedures for
expressing consent, typically through constitutional law.
However, this flexibility was counterbalanced by stricter rules in Part V of the VCLT, which govern
the invalidity, termination, and suspension of treaties. These make it more difficult for states to
withdraw from or challenge treaties after expressing consent.
In practice, most states prefer parliamentary ratification as the method of expressing consent to
treaties, reflecting the need for legislative oversight in foreign policy.
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For bilateral treaties, both parties must express consent for the treaty to take effect.
In contrast, multilateral treaties often require a minimum number of ratifications before entering
into force. This ensures that such treaties apply to a significant number of states.
However, some states have not ratified it, often due to objections to certain provisions. Despite this,
many of its principles are recognized as customary international law and are frequently invoked in
diplomatic and legal settings.
A treaty, before entering into force, must bear legal relevance for the signatory states.
Under the principle of good faith, these states cannot adopt a conduct in contrast with the object
of the treaty.
The signing is an indication of intent to engage in the necessary internal constitutional procedures
aimed at expressing its consent to become a party. This generates the legitimate expectation that
the state in question would not act on contrary to the object.
The manifest violation represents one of the causes of invalidity, together with fraud, error,
corruption and coercion.
It’s an exception that the cause of invalidity is successfully invoked by a contracting state  reflects
the pacta sunt servada principle, according to which a party may not invoke the provisions of its
internal law as justification for its failure to perform a treaty.
The VCLT includes provisions that allow a state to challenge the validity of a treaty under certain
conditions. One is Article 46, which permits a state to argue that a treaty is invalid if its conclusion
violated a domestic rule of “fundamental importance” regarding treaty-making.
However, this raises concerns about potential misuse. A state could agree to a treaty and later claim
invalidity based on its internal laws when it no longer wishes to comply.
To prevent such abuses, Article 46 must be interpreted within the broader framework of the VCLT
and the principle of good faith. This means that a treaty can only be invalidated if the violation of
constitutional rules was clear and significant at the time the state consented to the treaty.
Another key ground for invalidating treaties is their conflict with a peremptory norm of
international law, known as jus cogens. These are fundamental rules that protect the interests of
the international community, such as prohibitions on genocide, slavery, or torture. If a treaty
contradicts such a norm, it is considered void from the outset, reflecting the principle that certain
international obligations cannot be overridden by agreements between states.
The VCLT includes provisions about treaties that may be considered invalid if they violate
fundamental international norms. However, it does not clearly define which rules qualify as jus
cogens. Based on international legal practice.
While it may seem unlikely that a treaty would violate jus cogens, possible examples include an
agreement forming an offensive military alliance. If a state believes a treaty is invalid due to such
violations, Article 66 of the VCLT allows one of the treaty parties to bring the issue to the
International Court of Justice (ICJ), unless both parties agree to resolve it through arbitration.
However, only the parties to the treaty can challenge its validity, not any state in the international
community.
17
It is unlikely that a state that entered a treaty would later challenge it. A case might arise if there is
a major change in government, and the new leadership wants to distance itself from the treaty. In
such a scenario, the new government might simply withdraw from it.
Treaties don’t last indefinitely and can be terminated in different ways:
- Some treaties include an expiration date or allow for unilateral withdrawal.
- mutual agreement, explicitly or implicitly. However, problems can arise if a new treaty
replaces an old one without stating that it overrides the previous agreement. This can create
legal uncertainty about which treaty remains in effect.
Many treaties include sunset clauses  extend the treaty’s protections for a set period after
termination so that investors can still rely on its guarantees (usually used in Bilateral investment
treaties). They usually afford 10-year extension, during which the investors can still use protection.
Among the external ground for termination there’s the material breach of the treaty by one of the
parties, which makes ground for reciprocal conduct by other states parties. These can be
complemented with other forms of response based on the law of state responsibility regarding the
consequences of an internationally wrongful act  on this matter article 60 of the VCLT has put
down some rules.
-
pacta sunt servanda rebus sic stantibus  change of circumstances with respect to the
existing at the time the agreement was signed. This principle was established during the
negotiations in Vienna by the Western delegations and an Article (62) was made about it.
Substantially there are four conditions met for the cause of termination to by validly invoked:
1) The change must be assessed with respect to the circumstances known at the time of
the conclusion of the treaty.
2) Political changes may be relevant, but the principle of good faith always prevails and
prevents governmental changes invoked by a given state.
3) The change should have not been foreseeable at the time when the treaty was
concluded.
4) The circumstances subject to the change must have constituted a basis of the consent of
the parties to be bound by the treaty.
-
impossibility of performance: it can be invoked because of objective grounds; based on the
principle of good faith, it may not be invoked validly if the circumstances are the result of
the state’s conduct invoking it.
The consent of an agreement may be affected by reservations when a state would like to become a
party to a treaty except for some provisions.
A reservation is a unilateral statement made by a State when signing, ratifying or acceding to a
treaty and it purports to exclude or modify the legal effect of certain provisions of the treaty in their
application to that State.
Reservations allow states to tailor their commitments by excluding or modifying provisions; this way
a balance is ensured between broad participation and respect.
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Reservations are usually admissible as long as they don’t undermine the purpose of the treaty, and
it falls on each state party to assess their admissibility.
Under the VCLT, the latter may produce different effects rising a web of different legal relations
stemming from the same treaty.
4.The lack of a centralized system of assessment on the admissibility of certain reservation is
problematic in relation to human rights treaties where the negotiating states have avoided to rule
of the admissibility of reservations with a view to encouraging many ratifications.
States negotiating human rights treaties are often willing to accept flexibility and diversity in how
the treaty applies to different countries, to encourage more states to ratify it. This is common
because treaties are usually the result of complex compromises, and their texts are rarely so clear
that they don’t require interpretation.
Treaty interpretation is governed by customary international law, Articles 31 to 33 of the VCLT,
which are recognized even by states that are not parties to the Convention.
Article 31 sets out the main rules of interpretation:
- the text must be interpreted according to its ordinary meaning, that is, the everyday
meaning of the words.
- the intentions of the states (the parties) must be considered.
- the purpose and object of the treaty should guide the interpretation, often leading to
broader and more flexible results.
The balance between these elements is found in the contextual approach: a provision must be
interpreted not only by itself but in light of the treaty as a whole. Additionally, interpretation must
also take into account:
- subsequent agreements between the parties,
- later practice in applying the treaty,
- and other relevant rules of international law binding on the parties.
The travaux préparatoires (the negotiating history of the treaty) are considered a supplementary
means of interpretation under Article 32. In practice, however, international courts and tribunals
often refer to them to confirm and support an interpretation. These preparatory works are useful
when the ordinary meaning of the text is unclear.
The first duty of a court is to give effect to the natural and ordinary meaning of the words in their
context. If this meaning makes sense, the interpretation stops there. Only if the words are
ambiguous or unreasonable should the court turn to other methods.
International custom has been the main source of modern international law, starting in the 17th
century with the rise of nation-states. At that time, the leading actors were the Great Powers of
Europe. This is why customary international law is seen as developing from the usual practices of
states in their relations with each other.
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Over time, these repeated habits gained legal status, as states began to expect such behavior would
be mutually respected as binding rules.
Customary international law is based on two key elements:
1. State practice: There must be widespread and consistent practice by states over time.
2. Legal conviction: States must believe that this practice is carried out because it is legally
required. This is called opinio juris sive necessitatis.
An example is the respect for diplomatic immunity: states started to grant immunity to foreign
representatives, expecting that their own diplomats would receive the same treatment.
This approach, often described as rooted in natural law, worked well when the international
community was homogeneous—mainly European powers.
Even today, customary international law remains a key source of law. Alongside treaties, it is often
used by states to justify claims and by international courts and tribunals to settle disputes.
A key feature of customary international law is its general applicability. Unlike treaty law, customary
law applies to all states in the international community.
Customary international law is made up of two elements:
- State practice (actual behavior of states),
- Opinio juris (the belief that such practice is legally obligatory).
State practice can take many forms. It includes:
 Diplomatic actions, like official statements by government officials, protests through notes
verbales.
 Domestic practice, including legislation, court decisions, and administrative acts.
 Operational conduct by state agents, such as the behavior of the police, customs officers.
Even the conclusion of treaties (conventional practice) can provide evidence of state practice for
identifying customary law. If many states conclude similar treaties on a particular issue, this can
indicate the existence of a customary rule.
Importantly, the more widespread and uniform the practice is among states, the less time it takes
for that practice to crystallize into customary law.
While state practice and opinio juris are distinct elements, they are often identified using the same
evidence.
This dual process—looking at both what states do and why they do it—is essential in identifying
customary international law.
In international law, sources can help identify the existence and content of customary law. These
include:
•
International judicial decisions,
•
International agreements,
•
Resolutions of intergovernmental organizations,
•
And academic writings.
Each of these carries a different level of authority; for example, resolutions from international
organizations are particularly important because they reflect the collective diplomatic practice of
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states and can express collective opinio juris. However, their authority depends on factors like the
voting record and the specific wording used in the resolution.
It is also important to note that, although customary international law is unwritten by definition,
much of the evidence used to identify it is actually written. Examples include:
•
Court decisions,
•
Treaties,
•
Official statements,
•
And academic analyses.
This does not contradict the nature of customary law because no single document, by itself, proves
the existence of a custom.
In some cases, state practice can also include inaction or silence. If a state consistently does not
protest another state’s actions, this may be taken as acceptance and an indication of opinio juris.
International court decisions help identify customary law, but they are not binding precedents.
Under Article 59 of the ICJ Statute, judgments only bind the parties in that case. However, in
practice, courts usually follow their past rulings unless there’s a strong reason to change. For
example, in Cameroon v. Nigeria, the ICJ said it would generally stick to its earlier decisions.
As Dame Rosalyn Higgins noted, states pay close attention to ICJ judgments because they know the
Court aims to stay consistent.
According to the ILC, court decisions guide the identification of custom, but their weight depends on
the quality of reasoning, state acceptance, and the court’s authority. Importantly, decisions do not
freeze the law—custom can evolve. The ICC shows a similar pattern, as Article 21(2) of the Rome
Statute lets it apply rules as interpreted in its past judgments.
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5. General principles of law are the third source of international law, listed in Article 38(1)(c) of the
ICJ Statute.
According to Sir Hersch Lauterpacht, these are fundamental legal maxims found in different national
legal systems, drawn from both public and private law. They are identified by comparing rules
common to national systems.
The reason these principles were included in Article 38 was to ensure that international courts, like
the Permanent Court of International Justice and the ICJ, would not face a situation where no
applicable treaty or customary rule exists to settle a dispute non liquet (meaning “it is not clear”).
As explained in the Gentini case by the Italian-Venezuelan arbitral commission, rules prescribe
specific actions, while principles provide general guidance.
When no specific rule applies, but a state’s conduct goes against a recognized general principle, that
conduct can be considered unlawful. Therefore, general principles play a gap-filling role in
international law, helping ensure disputes can still be resolved even when no precise rule exists.
General principles of law serve two main functions in international law:
- The interpretative function is seen in Article 31 of the Vienna Convention on the Law of
Treaties (VCLT), which says treaties must be interpreted in good faith. This principle of good
faith comes from general principles common to national legal systems and helps guide how
treaties are read and applied.
- The corrective function is even more powerful. Some general principles are so fundamental
that they can override or invalidate conflicting treaty rules or customary law. These include
the constitutional principles of international law, such as:
 The sovereign equality of states,
 Pacta sunt servanda (agreements must be kept),
 norms of jus cogens (peremptory norms), like the bans on the use of force, torture,
slavery, and violations of self-determination.
Not all general principles from domestic law automatically apply in international law. Only those
suitable for relations between states are accepted. Once these principles are consistently used at
the international level, they evolve from being domestic to fully international in nature. At that
stage, they help ensure the consistency of the international legal system.
These general principles are both structural and substantive. They include core rules like pacta sunt
servanda (agreements must be kept), good faith, unjust enrichment, estoppel, res judicata (finality
of judgments), and the principle that wrongful acts must be redressed and compensated.
Over time, many of these principles have been codified, as seen in the VCLT provisions on treaty
invalidity and termination.
While often unwritten, these principles still serve their original gap-filling role under Article 38 of
the ICJ Statute, addressing cases where no treaty or customary rule applies. Today, they are
frequently cited in international practice and case-law, and the ILC is currently working on clarifying
their identification and function.
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6. In international law, rules originating from different sources can often supplement or
complement each other. At times, new rules are developed with the aim of advancing or creating
new law.
Unlike domestic legal systems, international law does not have a centralized legislature or a binding
precedent system (res judicata) that establishes a strict hierarchy among its sources. The main
exception is the body of peremptory norms known as jus cogens, which are universally binding and
cannot be derogated by states.
In general, there is no formal ranking between treaties and customary international law. This means
that a treaty can modify or derogate from an existing customary rule, but only for the states that
are parties to that treaty. Conversely, the development of new customary international law can
override prior treaty obligations, especially if the new custom reflects a general practice accepted
as law by the international community. This dynamic interaction reflects the flexible and
decentralized nature of international law.
6.1 The International Law Commission (ILC), in its 2006 report on the Fragmentation of International
Law, affirmed that when multiple norms address the same issue, they should be interpreted to
produce a single set of obligations.
This compatibility is assessed on a case-by-case basis by examining the content of the rules. Where
such compatibility exists, one rule may assist in interpreting another, acting as a clarification or
modification. In such cases, both norms apply together, in line with the contextual approach to
treaty interpretation.
A particularly significant form of compatibility arises between codification conventions and
customary international law. Codification treaties often interact closely with custom  his
relationship was clarified by the International Court of Justice (ICJ).
The Court identified three situations where a treaty rule binds even non-parties:
(a) when the rule was declaratory of existing custom at the time of the treaty’s adoption;
(b) when the treaty-making process helped crystallize a custom already in formation;
(c) when, following the treaty’s adoption, state practice and opinio juris consistent with the rule
have generated a new customary norm.
This framework highlights how treaties and custom can reinforce each other in the development of
international law.
6.2 In domestic legal systems, conflicts between rules are settled through a hierarchy of sources
defined by the Constitution. When rules from the same level conflict, lex specialis derogat generali
(the specific prevails over the general) and lex posterior derogat priori (the later rule prevails)
principles apply, often interpreted by a supreme or constitutional court.
In international law, conflict resolution is complex due to the absence of a central authority. Treaties
may derogate from custom and vice versa, except for jus cogens norms, which are non-derogable.
The principles of lex specialis and lex posterior apply differently: the VCLT gives priority to lex
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posterior, while international courts, like the ICJ, often favor lex specialis, especially in specialized
fields like humanitarian or investment law.
However, when two conflicting rules are specialis, determining which prevails is difficult. States
cannot use one obligation to justify breaching another, making this an issue of state responsibility
rather than legal hierarchy.
The problem deepens when rules have different recipients—for example, when a treaty with limited
parties conflicts with general custom or with another treaty involving different states. Here, states
must choose between compliance and breach in relation to different obligations. To manage this,
many multilateral treaties include clauses to establish priority rules and prevent conflicts.
7. In debates on the sources of international law, the concept of soft law often arises. The term
appears contradictory because a rule is either law or it is not. However, while soft law instruments
are not binding legal rules, they can have legal relevance as evidence of emerging law or as guidance
on state behavior.
Examples of such instruments include codes of conduct adopted by international organizations,
reports and draft articles by the ILC, UN General Assembly resolutions, final declarations from
diplomatic conferences, and treaties adopted but not yet in force.
While these instruments cannot themselves create binding law, they can contribute to the formation
of customary international law when supported by consistent state practice and opinio juris.
It is important to distinguish soft law from binding obligations that are framed in flexible terms,
such as due diligence obligations. These obligations require states to take all measures to achieve
certain results and are legally binding, though they allow for progressive realization rather than
imposing strict duties.
Such obligations are often accompanied by reporting requirements and parameters to measure
compliance. For example, the obligation to prevent transboundary harm is a due diligence
obligation: states must make their best efforts to prevent harm, but they are not responsible if harm
occurs despite those efforts.
Even before new customs are formed, soft law instruments can have legal effects. States that
participate in adopting such instruments and later act inconsistently may be held accountable under
the principles of good faith, reliance. As Oscar Schachter noted, while non-binding commitments are
political or moral, they still carry the expectation of good faith compliance, and states may be
stopped from acting contrary to their previous commitments.
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CHAPTER FOUR
1.International courts and tribunals consider domestic statutes, administrative regulations, and
court decisions when these are invoked or challenged by parties. These instances highlight the
dynamic interaction between international law and domestic legal systems.
The relationship between international law and municipal law is reciprocal. On one hand,
international law oversees and evaluates the domestic actions of states, particularly where they
affect foreign nationals, goods, or officials, or where they have transboundary environmental
impacts.
On the other hand, the effective operation of international law depends on its implementation at
the national level. As Judge Crawford emphasized, “many of the objectives of international law must
be realized within the domestic sphere”. This includes national measures regulating the treatment
of foreigners, the jurisdiction exercised over foreign diplomats, and the internal controls over
activities with international consequences.
States adopt different methods to recognize or transform international rules and obligations into
their domestic legal orders.
There are two principal theories concerning the relationship between international and domestic
law: monism and dualism.
- monist approach: international law and domestic law are seen as part of a single legal
framework, allowing international law to apply directly within the national legal system
without the need for further legislative action.
- dualist approach: treats the two systems as separate, requiring states to formally
incorporate international law into domestic law before it can have any effect internally.
Domestic law is highly relevant from the perspective of international adjudication.
International courts assess domestic laws and practices when determining whether a state has
fulfilled its international obligations. Additionally, domestic legal systems vary in their constitutional
approaches to the reception and application of international law, often reflecting broader
distinctions between common law and civil law traditions.
A critical issue arises when there is a conflict between domestic law and international obligations.
In such cases, it is necessary to determine which rule takes priority. The resolution of these conflicts
is central to ensuring compliance with international law and maintaining the coherence of the
international legal order.
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2. In cases of conflict, international law prevails, and failures to apply it correctly are seen as
enforcement shortcomings.
A key feature of monism is that international law has direct effect within domestic systems, creating
rights and obligations for individuals without requiring national legislation. Lauterpacht highlighted
that while international law is made for states, its ultimate subjects are human beings who should
be protected by it.
In the dualist approach, international law governs relations between states and organizations, while
domestic law regulates individuals, companies, and national administrations. International law must
be incorporated through domestic legislation to have effect internally. Without this process,
international obligations do not automatically apply within a state’s jurisdiction.
In practice, dualism better reflects the current state of affairs, as most states require international
law to be transformed before it applies domestically.
National constitutional systems vary in how they receive and apply international law, but under
international law, each state retains the sovereign freedom to choose its method of incorporation,
provided it meets its obligations in substance.
According to dualism, each legal system claims supremacy within its domain: domestic law governs
internally, and international law externally. Yet, states must ensure their internal laws do not breach
international obligations. Importantly, international agreements and customs result from states
exercising both their external and internal sovereignty. Thus, international law is not imposed but
is collectively created by states through their sovereign choices.
This collective ownership is well captured by the term law of nations, highlighting that international
law belongs to the global community of states and organizations.
3. The separation between international law and domestic law is confirmed by international legal
practice. Article 3 of the ASR states that whether a state’s act is internationally wrongful is
determined by international law, even if that act is lawful under the state’s internal law. This is
reinforced by Article 27 of the Vienna Convention on the Law of Treaties, which bars states from
using domestic law to justify treaty violations.
International courts and tribunals treat domestic law as a fact; they refer to national legislation and
decisions as factual evidence, not as part of international law.
Domestic courts take a similar approach when dealing with foreign law, often requiring expert
testimony to establish its content.
National laws and decisions can serve as evidence of state practice or opinio juris, contributing to
the formation of customary international law. They can also show whether a state is complying with
or breaching its international obligations.
Thus, while international and domestic law are distinct, domestic law still plays a key evidentiary
role in the international legal system.
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Article 12 of the ASR confirms that a state breaches an international obligation when its act does
not conform to what is required, regardless of the act’s origin or character. This reflects the principle
that international law operates separately from domestic law.
As a result of this separation, if an international court or tribunal finds that a domestic statute,
administrative act, or court decision breaches international law, it cannot invalidate that domestic
measure directly. Instead, the international body orders the state to bring its conduct into
conformity with international law, using its own legal system and methods.
The binding force of international court decisions stems from the consent given by states through
treaties or agreements conferring jurisdiction. For example, Article 94(1) of the UN Charter obliges
UN members to comply with International Court of Justice (ICJ) decisions in cases where they are
parties. If a state fails to comply with such a judgment or arbitral award, it commits a new
internationally wrongful act, in addition to the original breach found by the tribunal.
Thus, while international courts cannot alter domestic law directly, their judgments impose binding
obligations on states to remedy breaches through their own legal processes.
3.1 In Germany v. Italy (ICJ 2012), the Court found that Italy breached international law by allowing civil claims against
Germany for WWII crimes, enforcing foreign judgments, and attempting to seize German property, violating Germany’s
sovereign immunity. The ICJ ordered Italy to end these violations through domestic measures. Italy passed a 2013 law
to comply, but its Constitutional Court (Judgment No. 238/2014) declared the law unconstitutional, prioritizing victims’
rights and reopening cases against Germany.
Italian courts resumed judgments and enforcement actions, including the planned auction of German state properties
in Rome. In 2022, Germany filed a new case at the ICJ, accusing Italy of systematic violations and seeking provisional
measures. Italy then passed Decree-Law No. 36/2022, creating a compensation system to satisfy victims while
respecting Germany’s immunity. Following this, Germany withdrew its urgent request, though the main proceedings
continue.
4. The long-standing debate between monism and dualism in international law concerns the
relationship between international and national legal systems.
Most national legal systems operate in a dualist manner. They treat international law as distinct
from domestic law, and its application often depends on national procedures and constitutional
norms. Even in systems that appear monist, application and interpretation are ultimately controlled
by national courts. These courts tend to prioritize their own constitutional principles and domestic
legal values over conflicting international norms.
This brings us to the real crux of the matter: in cases where there is a conflict between international
law and domestic law, national courts usually decide which rules prevail. In most cases, domestic
law takes precedence unless the constitution explicitly gives priority to international obligations.
Even in jurisdictions with monist features, the extent to which international law is applied depends
on the degree of dualism present in that legal order.
27
Domestic constitutional rules governing the relationship between international and national law are
often phrased in broad and imprecise terms. As a result, their interpretation can vary depending on
the circumstances of a case or the prevailing legal climate.
When a domestic statute or court decision is given precedence over an international rule—
breaching the state’s international obligations—this may occur through inadvertence or as a
deliberate political decision.
The tendency to prioritize domestic law may also reflect aspects of a country’s legal culture,
particularly among judges who are primarily focused on domestic legal sources. This highlights the
importance of ensuring proper education and training in international law.
Many domestic lawyers mistakenly view international law as something imposed and therefore
hostile to national sovereignty. International law arises from the consent and expresses legal views
of states themselves, representing an exercise of their sovereignty.
Consequently, domestic constitutional practices that give precedence to international law—
whether applied directly or transformed into national law—reinforce the coherence of the domestic
legal system. Only when there is an overriding political reason might a state deliberately breach
international law to push for its modification.
5. Historically, until the 20th century, customary law was the primary source of international law.
This reflects a monist perspective, where international law and national law are seen as components
of a single legal order. Therefore, international customs were incorporated into domestic law
without requiring new legislation.
In the English common law tradition, this approach is embodied in the incorporation doctrine, which
holds that customary international law is automatically part of domestic law and should be applied
by national courts. However, this also places the burden on domestic judges to identify the current
content of international customs, which can be complex.
Under this doctrine, changes in international customary law automatically bring corresponding
changes in English law.
A key example is the 1977 case of Trendtex v Central Bank of Nigeria, where Lord Denning emphasized that international
law evolves and that English courts have applied these changes without needing parliamentary approval. He noted that
as public opinion shifted to condemn slavery, English courts adapted by applying the modern rules of international law.
Under the incorporation doctrine, customary international law is considered part of domestic law
and is directly applicable in national courts.  individuals in the UK can invoke international customs
in their defense before domestic courts.
However, in modern times, this doctrine has been moderated in both English and Scots law.
Customary international rules are incorporated automatically only when they do not conflict with
existing statutes or binding judicial precedents.
Once an international custom is recognized by a UK court of final authority, it becomes part of
domestic law and is binding under the principle of stare decisis. Moreover, Parliament and the
Government can transform an international custom into domestic law through legislation.
28
Generally, UK statutes and judicial decisions have aimed to conform with international law, although
rare cases of deliberate breaches have occurred, sometimes to encourage legal change.
When it comes to treaties, in Commonwealth countries, the Government is responsible for their
conclusion and ratification.
Since 1924, the Ponsonby Rule requires treaties to be presented to Parliament. Crucially, if a treaty
necessitates changes to domestic law, implementing legislation must be passed before ratification.
This contrasts with practices in other countries where such legislation often follows ratification after
significant delays.
The European Convention on Human Rights (ECHR) was incorporated into UK law by the Human
Rights Act 1998. This Act requires public bodies and courts to act consistently with the ECHR and
rulings of the European Court of Human Rights (ECtHR).
If domestic legislation is incompatible, courts issue a declaration of incompatibility, which doesn’t
invalidate the law but triggers a legislative process to amend it.
This “tempered incorporation” approach in UK law mirrors the long-standing practice in the United
States, where international law is part of federal law but subordinate to the US Constitution.
In the landmark 1900 case The Paquete Habana and The Lola, the US Supreme Court affirmed the doctrine that
customary international law is part of US law. The case involved two Spanish fishing vessels captured by the US Navy
during the Spanish-American War. The Court reversed a lower court’s decision, recognizing an international custom that
exempted peaceful fishing vessels from capture during wartime.
In its judgment, the Court declared that international law is incorporated into US law and must be applied by domestic
courts whenever relevant questions arise. Specifically, in the absence of a treaty, federal law, or prior judicial decision,
courts should look to “the customs and usages of civilized nations” to determine applicable rules. This ruling reinforced
the principle that international custom is directly enforceable in US courts unless overridden by clear domestic law.
In the United States, customary international law is not only incorporated through judicial doctrine
but also through specific statutes, such as the Alien Tort Claims Act (ATCA) of 1789.
This law grants US federal courts jurisdiction over civil actions brought by non-US citizens for torts
committed in violation of international law.
The statute was revitalized in the 1980 case Filártiga v Peña-Irala, where the federal court accepted jurisdiction over a
claim involving torture committed in Paraguay, recognizing that torture violates a binding rule of customary
international law. This case set a precedent for using the ATS to seek damages in US courts for international human
rights violations.
However, the US Supreme Court has since restricted the scope of ATS claims.
In Sosa v Alvarez-Machain (2004), the Court limited such claims to violations of well-established and universally
accepted norms of international law. In Kiobel v Royal Dutch Petroleum (2013), the Court further ruled that the ATS does
not authorize federal courts to hear cases lacking a strong connection to the US, rejecting the idea of universal or broad
extraterritorial jurisdiction under the statute.
Regarding treaties, Article VI(2) of the 1787 US Constitution—the Supremacy Clause—states that
treaties made under US authority are the “supreme law of the land,” binding on state courts even if
state laws conflict.
29
Despite this, US courts have generally presumed that domestic law should align with international
treaties in force, a principle dating back to the 1804 case Murray v The Charming Betsey. The
challenge arises from the judiciary’s discretion in deciding whether a treaty is self-executing.
6. In Italy, Article 10(1) of the Constitution establishes that the Italian legal system aligns itself with
the generally recognised rules of international law  customary international law automatically
becomes part of Italian law without the need for further legislation. This is called “constitutional a
priori transformation” —international customs are transformed into national law at the
constitutional level.
As a result, these international customs take precedence over any Italian law, whether it was made
before or after the custom, if the law conflicts with it.
However, the Italian Constitutional Court has the authority to block or limit this transformation in
cases where it conflicts with fundamental principles.
When it comes to international treaties, the process is different. According to Article 80 of the
Constitution, certain treaties require the approval of the Italian Parliament through a specific law.
These include treaties that:
•
Are political in nature,
•
Require arbitration or judicial settlements,
•
Affect the national territory,
•
Involve financial costs,
•
Or require changes to existing legislation.
So, while customary international law automatically becomes part of Italian law, treaties need
formal parliamentary approval through legislation before they have legal effect domestically.
In the Italian legal system, the process of incorporating international treaties involves both
parliamentary and executive powers. According to Article 80 of the Italian Constitution, the
Parliament must authorize the ratification of certain treaties through a law, particularly those of
political nature, involving arbitration or legal settlements.
The actual ratification is then carried out by the President of the Republic under Article 87(8).
Typically, the law authorizing ratification also contains provisions for the treaty’s implementation.
If the treaty’s provisions are self-executing, no further legislative action is needed. However, if not,
additional implementing legislation is required to make its rules operational domestically.
Following the constitutional reform of 2001, Article 117(1) explicitly states that both the State and
the Regions must exercise legislative power in compliance with EU law and international obligations.
This provision reinforces the principle that both international custom and treaties, once
incorporated, prevail over conflicting national statutes.
French law does not explicitly clarify whether international custom overrides inconsistent acts of
Parliament. In contrast, Article 55 of the French Constitution clearly establishes that duly ratified
treaties take precedence over domestic laws, both prior and subsequent.
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In Germany, the constitutional framework is more explicit. Article 25 of the Basic Law states that
general rules of public international law are part of federal law and take precedence over statutes,
directly creating rights and duties for individuals within Germany.
Furthermore, under Article 59(2), treaties requiring legislative approval become part of domestic
law once ratified.
German case-law confirms that ratified treaties have the same rank as federal statutes and may be
superseded by later legislation according to the principle lex posterior derogat priori (the later law
overrides the earlier one).
However, German courts also recognize that treaties regularly transformed into domestic law can
have direct effect, meaning individuals and companies can invoke them before national courts,
provided the treaty provisions are self-executing.
Germany offers the clearest constitutional basis for the primacy and direct applicability of both
customary international law and treaties.
Italy, after the 2001 reform, has strengthened the precedence of international law but allows for
constitutional review to limit its domestic effect, while France emphasizes treaty primacy but
remains less explicit on the domestic standing of international custom in conflict with parliamentary
acts.
The 1993 Russian Constitution integrates international law into its legal system.
Article 15(4) states that universally recognised principles and norms of international law and
international treaties are part of Russian law and should prevail over conflicting national legislation.
Specifically, it affirms that treaty rules override domestic laws when they differ.
Additionally, Article 17(1) guarantees human rights in accordance with international standards and
the Constitution.
In the 1990s, Russian courts, particularly the Constitutional Court, actively upheld the direct
applicability and effect of international law.
For example, in 1998, the Court struck down local residency permit rules (propiska system) for violating freedom of
movement, citing the ICCPR and Protocol No. 4 to the ECHR.
However, this openness declined over time. The 2020 constitutional amendments, especially Article
79, now limit the domestic effect of international decisions  it states that Russia will not enforce
international rulings that contradict its Constitution, signaling a shift towards constitutional
supremacy and reducing international legal influence, particularly in human rights matters.
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7. Across national legal systems, the relationship between international and domestic law generally
shows a blend of monist and dualist features, with many countries adopting a form of mitigated
dualism.
The core issue is which rule prevails when an international rule, once incorporated into domestic
law, conflicts with a national statute or final judicial decision.
In practice, domestic case law usually gives precedence to international rules that have been
incorporated or transformed into domestic law. This principle is often based on explicit
constitutional provisions or established judicial practice.
However, an important limitation applies: the so-called “controlimiti” (counter-limits) doctrine. This
means that even when international law is given a high or constitutional status, it must still be
compatible with fundamental constitutional principles. If there is a conflict, it falls to the national
constitutional or supreme court to decide.
Because these courts operate within national political contexts and enjoy significant discretion, their
judgments often reflect the prevailing political climate, despite their formal role as neutral guardians
of constitutional balance.
As such, while international law may formally take precedence, in reality, constitutional courts can
limit its domestic effect when they see a conflict with core constitutional values.
A comparative analysis of constitutional and supreme court case-law reveals much about how each
country balances international law and national sovereignty. In the past decade, however, there has
been a noticeable shift from openness to international legal values towards a more nationalist
closure.
Up until the early 2000s, debates about the place of international law remained within a broad
consensus. While national courts sometimes prioritized sovereignty and domestic law, they
generally framed their arguments within international legal standards.
International law served as a shared legal language, even when used to pursue national interests.
Courts recognized the global interdependence that links domestic and international security,
treating tensions between international and domestic law as technical and cultural issues rather
than overtly political ones.
However, this balance has started to erode. In recent years, nationalist trends have led courts and
governments to increasingly emphasize sovereignty over international commitments, marking a
political turn in what was once a primarily legal debate.
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8. In contemporary international law, there is an observable rise in juridical nationalism, where
states assert the supremacy of their domestic constitutional and judicial systems over international
obligations.
This often manifests as domestic judicial unilateralism — meaning national courts either ignore or
refuse to apply international law, even when it creates binding obligations. This trend is paralleled
by political unilateralism, where states withdraw from international agreements and cooperation
frameworks.
A prominent example is the practice of the United States judiciary and government. While
sometimes supporting each other, at other times they conflict on the application of international
law.
A key illustration of this is the series of US Supreme Court cases concerning the 1963 Vienna
Convention on Consular Relations (VCCR), specifically Article 36  establishes the right of foreign
nationals arrested or detained in a receiving state to communicate with their consular officers. It
obliges the receiving state to notify the consular post “without delay” and to inform the arrested
person of this right. It also gives consular officers the right to visit, communicate, and arrange legal
representation for their nationals.
The legal controversy in the US revolves around whether this treaty provision is self-executing —
that is, whether it creates rights that individuals can directly invoke in US courts. If so, failure to
inform a foreign national of their Article 36 rights could constitute a procedural violation, potentially
invalidating their criminal conviction.
However, US courts, including the Supreme Court, have often ruled that while the treaty creates
international obligations, it does not necessarily grant individuals enforceable rights in domestic
proceedings unless Congress passes implementing legislation. This position reflects a broader
nationalist trend where domestic legal authorities limit the domestic effect of international norms,
reinforcing the priority of national law over international commitments.
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CHAPTER FIVE
1. International law-making is participatory in nature, meaning that states and intergovernmental
organizations are both the creators and subjects of international legal rules. This participatory
character should encourage states to comply with international law, since they have a role in
shaping it.
This system contrasts with domestic law, where laws are imposed from above by legislative or
judicial authorities. Despite the participatory nature of international law, states do not always
comply perfectly with their obligations. While most rules are followed in practice, breaches do still
occur.
The expectation of consistent compliance assumes a unified legal identity of the state. Ideally, the
same state that enters into international agreements should also uphold them consistently.
However, as international law increasingly affects areas once considered domestic, the demands on
national governments have grown. This has led to administrative and legal overload in many states,
reducing the quality and coherence of their actions. As a result, some violations of international law
happen due to oversight or administrative failure.
The effective functioning of a state’s bureaucracy is essential for ensuring compliance with
international law.
However, within the state, there is often a disconnect between the officials involved in creating
international legal obligations and those responsible for implementing them.
This issue is made more complex by the separation of powers in most democratic states. While the
legislative and executive branches may take steps to align domestic law with international
obligations, the judiciary may act independently, sometimes resisting such alignment.
The Jurisdictional Immunities of the State case between Germany and Italy illustrates this: even after the Italian
government and parliament acted to comply with an International Court of Justice (ICJ) ruling, Italian courts continued
to make decisions that contradicted it.
These types of issues fall under the rules of state responsibility for internationally wrongful acts.
These rules govern how states may be held accountable when they breach international obligations,
whether through action or inaction.
Another important area is the duty of states to prevent harm to other states originating from their
territory (the principle of “use your property in such a way that you do not harm others”).
When private actors cause cross-border damage, the state may be held responsible if it failed to
prevent the harm due to negligence. However, if the activity was lawful but still caused harm, state
liability for lawful acts may apply.
To avoid being held responsible under international law, states often permit victims of
transboundary harm to seek civil liability from the private parties responsible. This can take place in
the courts of the state where the damage occurred or where the damage was suffered. These
related issues of state and civil liability will be explored in further sections.
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2. States generally follow international law, but breaches can still occur—by accident or as a
deliberate decision. In cases of inadvertent breaches, the responsible state may be unaware of the
relevant legal rule or may misinterpret it.
When a state believes another state has violated international law, it can invoke state responsibility.
To do this, it must prove two things:
1.
The factual conduct that allegedly caused the breach, and
2.
The legal rule that imposes the obligation said to have been violated.
However, if the injured state delays in reacting for a significant amount of time, it may lose the right
to make a claim under the principle of acquiescence  silence or inaction can imply acceptance of
the situation.
The law of state responsibility provides a framework for determining when an internationally
wrongful act has occurred and what consequences follow.
It’s important to distinguish between international state responsibility and other forms of legal
liability. For instance, a state can be sued in the courts of another country for violating that country’s
domestic laws, but that does not necessarily involve international law. Likewise, if a state breaches
a rule that is part of another state’s domestic legal system, this should not be treated as a violation
under international law.
A real example is the 2005 arbitration case between Brazil and Italy, which involved a dispute between their Ministries
of Defence over a military aircraft contract governed by English contract law. Because the legal obligation in question
arose from English domestic law and not international law, the issue did not fall under the law of international state
responsibility.
The rules of international state responsibility are primarily designed to regulate legal relationships
between states, but they are also applied in cases where individuals or companies bring claims
before international courts and tribunals. Although private parties are the applicants, they are often
seen as exercising rights that protect the interests of states.
International state responsibility forms a single, unified regime, regardless of the type of the
obligation breached.
This is unlike domestic legal systems, which typically separate liability into categories such as
contract, tort, or crime. The same international rules apply whether the breached obligation stems
from a treaty, customary international law, general principles of law.
These rules are secondary rules, as codified by the International Law Commission (ILC) in the Articles
on State Responsibility (ASR). They do not impose specific duties on states, but rather define the
legal consequences of breaching such duties  if a state commits an internationally wrongful act, a
legal relationship arises between the breaching state and the injured state—entitling the latter to
seek remedies such as reparation or countermeasures.
Invoking state responsibility is distinct from treaty-based remedies. For example, even if a state
reacts to a treaty breach by suspending or terminating the treaty under Article 60 of the Vienna
Convention on the Law of Treaties (VCLT), it may still pursue a state responsibility claim—
particularly for compensation or other lawful countermeasures beyond the treaty framework.
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2.1.1 According to Article 2 of the Articles on State Responsibility (ASR), an internationally wrongful
act occurs when a state engages in conduct that violates an international obligation binding upon
it, and that conduct is attributable to the state.
First, damage is not required for an internationally wrongful act to exist. The mere breach of an
international obligation is sufficient to trigger state responsibility. Some international rules may
involve harmful consequences but, in these cases, the obligation itself is framed in terms of avoiding
damage.
Examples include:
 The obligation not to expropriate foreign nationals arbitrarily or discriminatorily.
 The duty to respect the jurisdictional immunity of foreign states.
These examples highlight the importance of declaratory judgments in international law. These are
rulings that officially declare a state’s conduct to be wrongful, even without ordering reparations.
They often serve to reaffirm legal obligations and require the wrongdoing state to provide
assurances of non-repetition.
In international law, fault—meaning intent or negligence—is not a necessary element for a state to
be held internationally responsible for a wrongful act. This is because fault, as a psychological or
subjective element, applies to individuals.
If international law required proof of fault on the part of state officials for an internationally
wrongful act to exist, very few cases of state responsibility could ever be established.
A good illustration is the Norstar case between Panama and Italy, decided by the International Tribunal for the Law of
the Sea (ITLOS). In that case, the Italian authorities had ordered the seizure of the Norstar, a Panamanian-flagged vessel,
based on Italian criminal law. They believed they had jurisdiction under Article 33 of the United Nations Convention on
the Law of the Sea (UNCLOS), which allows coastal states to enforce customs and fiscal laws in a contiguous zone—an
area extending up to 24 nautical miles from the coast.
However, ITLOS found that Italy had not formally proclaimed such a zone in its domestic legislation at the time.
Therefore, the seizure occurred on the high seas, where Italy had no jurisdiction under international law. As a result,
Italy’s actions breached Article 87 of UNCLOS, which guarantees freedom of navigation.
Importantly, ITLOS did not consider whether the Italian authorities intended to breach international law, nor did it
require proof that they had failed to act with due diligence. The only relevant question was whether the conduct
objectively violated an international obligation. Once that was established, the act was deemed internationally
wrongful.
This case confirms a fundamental principle of state responsibility: the presence of fault or intent is
not required to establish that a state has committed an internationally wrongful act. The focus is on
the objective breach of a binding international rule, not the subjective mindset of the state organs
involved.
While intent or fault is generally not required for a state to be held internationally responsible,
negligence can still be relevant—but only in specific cases where the primary rule breached imposes
an obligation of due diligence. In such instances, the standard of care expected is built into the
primary obligation itself. Therefore, negligence is not a separate requirement for state
responsibility; it simply reflects the type of conduct the rule seeks to prevent.
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Similarly, some international rules require a qualified mental state for a breach to occur. For
example, the crime of genocide requires proof of specific intent (dolus specialis)—the deliberate
intention to destroy a national, ethnic, racial, or religious group. In such cases, intent becomes part
of the primary obligation and must be established for the violation and responsibility to arise.
In addition to a breach of an international obligation, there must also be attribution of the conduct
to the state.
Since states are abstract legal entities, they act through individuals or bodies—organs of the state—
that perform state functions. This is true whether the conduct is in accordance with domestic law
or not. According to Article 4(1) of the Articles on State Responsibility (ASR), a state is responsible
for internationally wrongful acts committed by:
•
Its parliament
•
The central government
•
Local or regional authorities
•
The police
•
The courts and other judicial bodies
Responsibility still arises even if these organs act beyond their legal authority (ultra vires).
States cannot avoid international responsibility by invoking their domestic laws, including
constitutional provisions such as the independence of the judiciary or the autonomy of local or
federal authorities. Under international law, a state is responsible for any act or omission that
violates an international obligation, regardless of its internal legal structure.
The conduct that gives rise to state responsibility may take the form of either acts (commissions) or
failures to act (omissions). Whether the state is required to act or to abstain depends on the nature
of the primary obligation:
 Negative obligations (obligations not to do) are breached by active conduct that violates
them. These are often easy to detect. Examples include:
o Unlawful expropriation without compensation
o Conducting police actions inside a foreign embassy or consulate
o Denial of justice by domestic courts
o Use of force against another state’s territory
 Positive obligations (obligations to do) are often linked to the duty to prevent harm. Breach
occurs when the state fails to act diligently to avoid risks. However, the state’s failure to
prevent or control that act through appropriate measures.
If a chemical factory owned by a private company in State A pollutes the environment of State B,
State A is not responsible for the company’s actions directly. However, it could be held
internationally responsible if its authorities failed to:
•
Require a valid environmental permit
•
Conduct an Environmental Impact Assessment (EIA)
•
Monitor compliance with environmental standards
In these cases, the breach lies in the omission—the failure to exercise due diligence as required by
international law.
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Under international law, a state is generally not responsible for the conduct of private individuals
or non-state actors, such as protesters or private corporations. However, this principle has
important exceptions.
First, a state may be responsible not for the private conduct itself, but for its own failure to act. If
it’s proven that state organs did not take all reasonable measures to prevent unlawful acts, such as
the takeover of an embassy or environmental harm caused by a company, then the state may be
held internationally responsible for that omission. This reflects a duty of due diligence, meaning the
state must actively prevent foreseeable harm when it can.
Additionally, if state officials commit wrongful acts while performing their official duties, those acts
are attributable to the state, even if the officials act beyond their authority or against their
instructions. The key condition is that they are acting in their official capacity.
Responsibility can also arise from omission in cases where other state officials, knowingly allow
wrongful conduct to happen. If they are aware of the unlawful actions of an official and fail to
intervene, the state may be held responsible.
There are also two exceptions where the conduct of private individuals can be attributed to the
state. The first is under Article 8 of the ASR, which says that if private individuals act on the
instructions of, or under the direction of, the state, their conduct may be considered an act of the
state. However, the International Court of Justice has made clear that the threshold for proving this
kind of control is very high.
The second exception is under Article 11 of the ASR, which provides that if a state openly
acknowledges and adopts the conduct of private actors as its own, it can be held responsible.
2.1.2 Under international law, a state’s conduct that would otherwise breach an international
obligation may be excused in specific situations known as circumstances precluding wrongfulness,
as set out in Articles 20 to 25 of the Articles on State Responsibility (ASR). These are exceptional
circumstances which mean that the conduct is not considered internationally wrongful, even though
it technically violates an international obligation.
One of the key grounds is consent, regulated by Article 20 ASR. If one state (State A) gives valid and
prior consent to another state’s conduct (State B), that conduct does not amount to an
internationally wrongful act.
This consent must be given before the conduct occurs, and it must be clearly expressed and valid
under international law. However, if the conduct occurs without prior consent and the affected state
does not object afterward, this subsequent inaction or acquiescence might prevent the state from
later invoking responsibility. But this only affects whether the state can pursue the claim. In this
sense, consent removes the wrongfulness itself, while acquiescence merely affects the procedural
right to react (as noted in Article 45(b) ASR).
38
Another circumstance is the use of countermeasures, outlined in Article 22 ASR. These are acts that
would normally be wrongful but are taken in response to a previous international wrong committed
by another state.
To be lawful, countermeasures must be proportionate and cannot involve breaches of peremptory
norms (jus cogens).
Additionally, Article 26 ASR makes it clear that no circumstance precluding wrongfulness can justify
breaches of peremptory norms of general international law. These norms are universally binding
and cannot be derogated from necessity, or countermeasures.
Another exception arises in the context of actions authorized by the United Nations Security Council.
When the Security Council determines that there is a threat to international peace and security, it
may authorize measures like arms or economic embargoes. These are known as sanctions, and
when carried out in compliance with a Security Council resolution, they do not constitute wrongful
conduct under international law.
Since the 9/11 attacks, the Security Council has also employed targeted sanctions, directed at
individuals involved in terrorism, and because they are authorized under Chapter VII, they preclude
the wrongfulness of what would otherwise be a breach of individual rights or state sovereignty.
Given the current rise in international tensions among some of the five Permanent Members of the
UN Security Council—China, France, Russia, the United States, and the United Kingdom—it has
become increasingly unlikely that Chapter VII resolutions will be adopted soon.
Under the UN Charter, such resolutions require that none of the Permanent Members cast a veto.
Since the 1960s, abstentions are permitted and do not count as a veto, but the current geopolitical
climate makes consensus difficult.
Considering this, regional organizations have taken on a more prominent role in responding to
international crises.
Another key circumstance precluding wrongfulness is self-defense, as recognized in Article 21 of the
Articles on State Responsibility and Article 51 of the UN Charter. When a state is the victim of an
armed attack or act of aggression, it has the right to use force in self-defense.
However, it must be proportionate and in accordance with international humanitarian law. This
ensures that even in situations of legitimate self-defense, legal and ethical limits are respected.
Importantly, recognizing self-defense as a ground that precludes wrongfulness actually reinforces
the general prohibition on the use of force in international law. It shows that force is only permitted
under strict conditions, thereby strengthening the legal norm against its use.
One of the most controversial circumstances precluding wrongfulness under international law is
necessity, as codified in Article 25 of the ASR. While the existence of this rule has never been denied
by international courts or tribunals, its application has been limited.
When states invoke necessity to justify conduct that would otherwise be in breach of international
obligations, international tribunals have almost always rejected the defense—because the factual
circumstances of the case failed to meet the very strict legal requirements.
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According to Article 25 ASR, necessity can only be invoked in exceptional situations, and when two
conditions are met:
1. The wrongful conduct must have been the only way for the state to safeguard an essential
interest.
2. That interest must have been under grave and imminent peril.
In addition, the rule specifies that necessity cannot be invoked if the state itself has contributed to
the situation it seeks to rely on, or if the obligation breached is derived from a peremptory norm
(jus cogens).
An example comes from investment arbitration cases involving Argentina. After its severe financial crisis in 2001,
Argentina tried to invoke necessity to justify breaches of its obligations under investment treaties. However, in most
cases, tribunals rejected the defense. The reasoning was either that the measures Argentina took were not the only
means available, or that Argentina had contributed to the crisis through its prior economic policies. These decisions
illustrate how strictly necessity is applied and confirm its exceptional nature.
It’s also important to understand that, even when necessity is successfully invoked and the conduct
is no longer considered internationally wrongful, this does not eliminate the duty to compensate for
any material damage caused. This is established by Article 27(b) ASR, which makes clear that
invoking a circumstance precluding wrongfulness does not affect the question of compensation.
The amount of compensation might be lower than in cases of full international responsibility, but
the obligation to repair harm remains.
Lastly, necessity is a temporary justification—it only precludes wrongfulness for as long as the
exceptional circumstances persist. Once the situation stabilizes, the state must resume full
compliance with its international obligations.
2.2 When an internationally wrongful act occurs, it gives rise to a secondary legal relationship
between the responsible state and the injured state. This legal relationship is generally bilateral,
reflecting the reciprocal nature of most primary international obligations, which are typically owed
from one state to another.
However, this bilateral framework must be reconsidered when dealing with breaches of erga omnes
obligations, which are owed to the international community as a whole and derive from peremptory
norms (jus cogens). In such cases, the legal consequences and rights of invocation may extend
beyond a single injured state, allowing for a broader response.
The main consequence of a breach of international law is the obligation to provide reparation. As
famously stated in the Factory at Chorzów case by the Permanent Court of International Justice,
reparation must wipe out all the consequences of the illegal act and restore the situation that would
have existed if the act had not occurred. This principle was reaffirmed in Article 31 of the ASR, which
states that the responsible state is under an obligation to make full reparation for any injury.
40
Reparation can take three forms:
1. Restitution – aiming to restore the situation that existed before the wrongful act. This may
include physical restitution, or legal restitution.
2. Compensation – if restitution is not possible or sufficient, monetary compensation is owed.
3. Satisfaction – typically symbolic in nature (such as an apology), used when moral damage or
dignity is involved.
In cases involving continuing wrongful acts, such as the unlawful detention of a foreign national or
the seizure of a foreign vessel, the obligation of reparation also includes the cessation of the
wrongful conduct. Ending the unlawful act restores the status quo and thus satisfies the restitution
obligation.
In cases where restitution is not possible, international law provides that the responsible state must
offer proportionate compensation to the injured state. This principle ensures that reparation
remains effective.
The World Trade Organization (WTO) and international investment arbitration systems approach
this obligation differently.
Under the WTO dispute settlement mechanism, panels typically give priority to restitution, requiring
the offending state to adjust tariffs or to amend domestic legislation to bring its conduct back into
compliance. This practice strengthens the underlying international obligations and reinforces the
trade relationship between the parties.
By contrast, in investment arbitration, tribunals generally prioritize the payment of compensation,
frequently accepting it as a default form of reparation. This reflects the fact that foreign investors
often lose trust in the host state’s authorities and are not interested in restoring the relationship.
Compensation in this context helps to safeguard investors’ economic interests and can also benefit
the host state by preserving its sovereign regulatory space.
Another important consequence of an internationally wrongful act is the right of the injured state
to take countermeasures. These measures aim to pressure the wrongdoing state to cease the
violation and provide appropriate reparation.
More broadly, countermeasures are a form of self-help, reflecting the decentralized nature of the
international legal system.
Unlike domestic legal systems, international law lacks a centralized enforcement mechanism.
Although the United Nations Security Council was designed to provide a centralized response to
threats to international peace and security, its effectiveness is often limited by political divisions
among its five Permanent Members (PMs).
Under Articles 27(2) and 27(3) of the UN Charter, decisions on procedural matters require nine
affirmative votes, while substantive decisions need nine votes including the concurring votes of all
five PMs. This grants each PM a veto power, enabling any one of them to block Security Council
action.
41
2.2.1 In the structure of the international law of state responsibility, the legal consequences of a
wrongful act are relatively straightforward when they involve traditional bilateral obligations—
those based on reciprocity between two states.
In such cases, if one state breaches an obligation owed to another, the injured state has a clear right
to invoke responsibility, claim reparation, and, if necessary, take countermeasures to ensure the
wrongful conduct is ceased and remedied.
However, modern international law has evolved to include a special category of obligations known
as erga omnes obligations, which are owed to the international community. These obligations are
often associated with peremptory norms of international law.
Jus cogens rules are those from which no derogation is permitted, and any treaty conflicting with
such rules is considered null and void under Article 53 of the Vienna Convention on the Law of
Treaties (VCLT).
Despite this strong legal framing, Article 53 does not specify which rules qualify as jus cogens. It
offers only a general definition, describing them as norms “accepted and recognized by the
international community of States as a whole” from which no derogation is allowed.
A concrete step in identifying erga omnes obligations came with the International Court of Justice’s
(ICJ) decision in the 1970 Barcelona Traction case.
The Court distinguished between obligations owed specifically to another state and obligations
owed to the international community. It stated that obligations erga omnes are of such importance
that all states have a legal interest in their protection, regardless of whether they are directly
affected. These obligations include:
•
The prohibition of aggression
•
The prohibition of genocide
•
Fundamental human rights norms, such as protection against slavery.
This concept means that any state can invoke the responsibility of a wrongdoing state when such
obligations are breached, even if it has not suffered direct injury. This reflects a shift from a system
based on reciprocity to one that incorporates the protection of collective interests.
While the law of state responsibility traditionally revolves around bilateral relationships and
remedies, it now also recognizes that certain breaches affect the whole international community,
allowing for broader enforcement.
The International Law Commission (ILC) codified this development in the ASR for Internationally
Wrongful Acts. One of the key innovations is found in Article 48(1), which allows states other than
those directly injured by an internationally wrongful act to invoke the responsibility of the
wrongdoing state in specific situations.
According to Article 48(1), a state that is not materially affected by the breach can still act if:
 the obligation breached is owed to a group of states, and it is established to protect a
collective interest of that group.
 (b) the obligation breached is owed to the international community.
42
Under these circumstances, the invoking state may:
 Raise the breach diplomatically;
 Have locus standi to bring the case before an international court or tribunal;
 Take countermeasures in support of the injured state — for instance, economic sanctions.
A notable example of this practice is the economic sanctions imposed by the European Union (EU) and its member states
against Russia, in response to the annexation of Crimea in 2014 and the invasion of Ukraine in 2022. These measures
were taken to support Ukraine and uphold international legal order.
However, this expansion of the right to invoke responsibility raises concerns.
Allowing states that are not materially injured to take countermeasures introduces a potential risk
of abuse, especially by powerful states with the economic and political resources to impose
burdensome sanctions. These countermeasures, while intended to protect international law, could
be used as tools of political or economic coercion, rather than legitimate enforcement.
This issue reflects a broader challenge in international law: while the law of responsibility is adapting
to a more multilateral international system, enforcement remains decentralized. Without a central
authority to regulate or authorize these countermeasures, there is always a risk that such powers
may be used selectively or opportunistically.
3. In domestic legal systems, the term “liability” generally means legal responsibility and can take
different forms depending on the type of legal rule that has been violated.
Common types include civil liability, such as for breach of contract; tort liability, which concerns
harm caused outside a contractual relationship; and criminal liability, where a person is responsible
for committing a crime.
A particularly relevant concept is that of strict liability, also known as objective liability. This concept
is found in both common law (as “strict liability”) and civil law systems (as “objective liability”).
The key characteristic is that it does not require proof of fault to establish responsibility.
In tort law, a person can be held liable for causing harm, even if they did everything possible to avoid
it. Similarly, in criminal law, strict liability offences can result in punishment even when there is no
intent or fault.
Normally, international responsibility arises only when a state commits a wrongful act, i.e., a breach
of an international obligation with attribution to the state.
An exception is found in special treaty regimes, most notably the 1972 Convention on International
Liability for Damage Caused by Space Objects. According to Article II of this convention, a launching
state is liable for damage caused by its space objects to persons or property or to aircraft. This means
the state is obliged to pay compensation regardless of whether it has committed a wrongful act.
This treaty-based rule reflects the understanding that in some highly risky activities states should
bear responsibility for harmful consequences, even in the absence of wrongful conduct, to ensure
protection for victims and promote safe practices.
43
In the development of international environmental law, the principle of prevention of
transboundary harm has played a key role. This principle is rooted in the Roman law maxim sic utere
tuo ut alienum non laedas, meaning: “use your property in such a way as not to harm others.” In
international law, this has evolved into the “no-harm rule”, which obliges states to ensure that
activities do not cause environmental damage to other states beyond national jurisdiction.
This rule has been affirmed in several legal cases and statements.
A major recognition came in the 1996 Advisory Opinion of the ICJ on the Legality of the Threat or
Use of Nuclear Weapons, in which the Court stated that exists a general obligation of states to
ensure that activities respect the environment of other states and of areas beyond national control.
The ICJ confirmed that this obligation is now part of customary international law in the field of
environmental protection.
Initially, in the 1980s, efforts were made within the ILC to codify this obligation as a duty—meaning
that any occurrence of transboundary harm would automatically be considered a breach. This
approach aimed to impose strict liability for environmental damage.
However, after further study and input from governments, the ILC shifted to a more practical and
flexible interpretation. The obligation was framed in terms of due diligence rather than strict
liability.
Under this due diligence standard, the state has a duty to take all appropriate preventive measures,
based on its available resources and capacities, to minimize the risk of harm. This means states are
required to regulate, monitor, and assess potentially harmful activities within their jurisdiction,
especially those considered hazardous.
The no-harm rule, understood as a due diligence obligation, was formally codified by the
International Law Commission in its 2001 Draft Articles on the Prevention of Significant
Transboundary Harm from Hazardous Activities. These articles were endorsed by the UN General
Assembly in both 2001 and 2006.
When transboundary environmental harm occurs despite a state’s failure to meet this due diligence
obligation, the situation falls under the international law of state responsibility. In such cases, the
state’s omission amounts to a breach of an international obligation, and full reparation may be
required.
However, a different legal regime applies in situations where transboundary harm occurs even
though the state has complied with its due diligence obligations. In such cases, the state has not
committed a wrongful act, but harm has still occurred, triggering state liability without wrongdoing.
This complementary regime introduces new primary obligations for the state from whose territory
the harm originated. These obligations include:
 Taking appropriate measures to eliminate or mitigate the harm;
 Consulting and cooperating with the affected state;
 Negotiating compensation, even though it would not reach the level of full reparation
required.
44
These principles are codified in the 2006 ILC Draft Principles on the Allocation of Loss in the Case of
Transboundary Harm Arising out of Hazardous Activities. This aims to balance the sovereign right of
states to pursue hazardous but lawful activities with the interests of other states affected by
environmental harm, ensuring fairness and cooperation.
In the context of international environmental law, it is important to recognize that few inter-state
disputes involving transboundary harm have been brought before international courts or tribunals.
This limited practice persists despite the existence of well-established rules on state responsibility
and liability, which provide a legal foundation for resolving such disputes.
One key reason is the growing preference for addressing transboundary harm through domestic
legal systems, particularly by enabling victims to bring claims directly before national courts against
the private operators responsible for the damage. This shift reflects three main considerations:
1. Avoiding reliance on diplomatic protection: Under traditional international law, individuals
cannot bring claims against foreign states directly and must rely on their state to invoke
diplomatic protection. This is a discretionary power  a state is not obliged to act, leaving
victims uncertain about access to justice.
2. Jurisdictional limitations of international courts: Even if a state is willing to act on behalf of
its nationals, this does not guarantee that the dispute will be resolved judicially.
3. Economic fairness within the origin state: When damage results from the activities of a
private operator, relying on inter-state mechanisms may result in the state having to
compensate for harm caused by private entities. This shifts the financial burden from the
polluter to the state and its taxpayers, making the public pay for the risks taken by profitmaking businesses. National liability regimes ensure that private actors bear the costs of
their own harmful activities, aligning with principles of economic justice.
This rationale is clearly reflected in Principle 13 of the 1992 Rio Declaration, which urges states to:
 Develop national legal systems for liability and compensation in cases of pollution and
environmental harm;
 Cooperate internationally to strengthen legal frameworks dealing with transboundary
environmental damage.
45
CHAPTER 6
1. Article 2(3) of the United Nations Charter states that all Member States shall settle their
international disputes by peaceful means, in a manner that international peace and security, are not
endangered. This principle is further developed in Chapter VI of the Charter, which is titled “Pacific
Settlement of Disputes.”
Until the early 20th century, the use or threat of force—commonly referred to as gunboat
diplomacy—was a lawful accepted way to resolve disputes between states. Powerful countries
often used military pressure to protect their interests, especially when dealing with weaker nations.
This practice began to be challenged by an increasing number of states, particularly those in Latin
America, who were frequently exposed to coercive measures.
The United States also supported this opposition, partly for geopolitical reasons. The devastating
experiences of the First and Second World Wars further reinforced the need to move away from the
use of force in international relations.
A key historical episode that illustrates this shift is the Venezuelan crisis of 1902–1903. In that case,
the United Kingdom, Germany, and Italy imposed a naval blockade on Venezuela to recover unpaid
public debts and to seek compensation for damages suffered by their nationals during the
Venezuelan civil war (1859–1863). At the time, this kind of military intervention was still legally
justified under international law.
However, the incident sparked debate and contributed to a growing movement to limit the use of
force. It was one of the factors that led to the Second Hague Peace Conference in 1907, promoted
by U.S. President Theodore Roosevelt  strengthen legal mechanisms for peaceful dispute
settlement, such as arbitration and mediation.
Article 2(3) and the ban on the use of force represent a major legal and historical development. They
mark the transition from a system where force was a legitimate tool of diplomacy, to one where
peace, justice, and the rule of law are the guiding principles in the resolution of international
disputes.
The UN Charter’s provisions on the peaceful settlement of disputes must be understood considering
earlier international legal developments. Notably, the 1907 Hague Convention for the Pacific
Settlement of International Disputes, laid important groundwork. In that same year, the Convention
Respecting the Limitation of the Employment of Force for the Recovery of Contract Debts. These
conventions signaled a gradual shift from the lawful use of force in international relations to a legal
framework prioritizing peaceful resolution.
Under Article 33(1) of the Charter, if a dispute threatens peace and security, the parties are required
to seek a solution by peaceful means.
This obligation is now considered customary international law, It has been reaffirmed by key UN
General Assembly declarations:
 The 1970 Declaration on Principles of International Law concerning Friendly Relations and
Co-operation among States, and
 The 1982 Manila Declaration on the Peaceful Settlement of International Disputes.
46
A crucial principle in this area is good faith. States are not only required to choose a peaceful
method, but they must genuinely try to resolve their disputes. If one peaceful attempt fails, they
are still obligated to continue seeking other peaceful solutions.
2. Under public international law, an international legal dispute is a disagreement between states,
or between states and intergovernmental organizations, governed by international law. While this
may sound straightforward, it is important not to take it for granted.
Not all disputes involving states qualify as international legal disputes. Some might be resolved in
domestic courts or through international arbitration, but they do not necessarily fall under the
domain of public international law.
Other types of disputes, such as:
- Human rights cases, involving individuals and states before international human rights
courts,
- Disputes between private investors and the host state under investment law.
belong to specialised areas of public international law, which are treated separately.
There is no codified definition of an international dispute in international law. However, defining
the concept is essential because many international courts and tribunals can only exercise
jurisdiction when there is a “legal dispute” between the parties.
One of the most important early definitions comes from the Permanent Court of International
Justice (PCIJ), which was the predecessor of the ICJ. In its 1924 decision in the Mavrommatis
Palestine Concessions case, between Greece and the United Kingdom, the PCIJ stated:
“A dispute is a disagreement on a point of law or fact, a conflict of legal views or of interests between
two persons.”
Later cases have added qualifications and clarifications. For example, it is not enough that one party
subjectively believes there is a dispute; there must be an actual disagreement that is objectively
verifiable. Courts often examine the conduct and statements of the parties to determine whether a
real and specific legal dispute exists.
In public international law, a legal dispute typically involves two legal persons. International legal
disputes fall under the scope of international law, and for a court like the International Court of
Justice (ICJ) to exercise jurisdiction, there must be a genuine legal dispute between the parties.
It might seem as though each element in that definition could independently qualify as a dispute.
However, in practice, these elements must be present cumulatively.
For example, a mere divergence of legal opinion or a general conflict of interests between states
does not establish the existence of a legal dispute. States may frequently have differing views or
competing interests without this leading to a formal legal conflict.
This point was clarified in the ICJ’s 1962 judgment in the South West Africa cases, where the Court
had to decide whether there was a dispute between Ethiopia and Liberia, and South Africa:
“It is not adequate to show that the interests of the two parties are in conflict. It must be shown that
the claim of one party is positively opposed by the other.”
47
This approach was confirmed in the 2005 Certain Property case between Germany and
Liechtenstein. The ICJ held that a legal dispute existed because Liechtenstein had made claims of
fact and law that Germany expressly denied. The Court concluded:
“By virtue of this denial, there is a legal dispute between Liechtenstein and Germany.”
An important question in international law is whether the opposition required for the existence of
a legal dispute must always be express, or whether it can be inferred from silence or inaction.
At first glance, one might think that if a state does not explicitly deny or object to a claim made by
another state, this could be interpreted as acquiescence. However, international case law has
consistently rejected this idea. The short answer is no: a lack of response does not automatically
mean acceptance of the claim.
Why? Because if silence were always treated as acquiescence, a state could avoid its obligation to
negotiate in good faith simply by ignoring claims.
In fact, international courts, especially the ICJ, have repeatedly held that:
“The existence of a dispute may be inferred from the failure of a State to respond to a claim in
circumstances where a response is called for.”
So, silence—when a reply is expected—can be seen as implied opposition, especially if the conduct
being complained of continues.
Often, it’s not easy to separate legal and factual issues. Interpretation of legal rules almost always
depends on how they apply to a given factual situation. As a result, most international disputes
involve a combination of both law and fact. There is no strict line between interpretation and
application of law in practice.
In international law, the existence of political aspects in a dispute does not prevent it from being
classified as a legal dispute. This principle is crucial, particularly for jurisdictional purposes, because
international courts and tribunals can only hear legal disputes.
As the International Court of Justice (ICJ) famously stated:
“The fact that [a] question also has political aspects, as, in the nature of things, is the case with so
many questions which arise in international life, does not suffice to deprive it of its character as a
legal question.”
This means that even if a dispute is part of a broader political conflict, it can still be judged as a legal
dispute if it involves a claim of a breach of international law opposed by another state.
This distinction is not only important from a legal standpoint but also from a political one.
By isolating the legal aspects of a broader political conflict, states may be able to resolve specific
legal issues through adjudication or negotiation, without needing to solve the entire political dispute
at once. This “piecemeal” approach can help reduce tensions and may benefit specific groups within
states who are directly affected by the legal issue but not involved in the broader political conflict.
Moreover, because international disputes are often complex, multiple methods of settlement can
be used together.
48
As previously discussed, a legal dispute arises when one state makes a claim that another state
breached an international obligation, and that claim is opposed by the other state. Typically, this
leads to the pursuit of reparative justice, such as restitution or compensation.
However, in certain cases, such as disputes over:
•
shared natural resources (e.g. transboundary water or oil),
•
territorial or maritime boundaries,
states often seek distributive justice rather than purely compensation for a breach. In such disputes,
settlement efforts may involve negotiations, declaratory judgments, or agreements that divide the
rights fairly between the parties.
Importantly, even in these “allocation” disputes, there may also be an element of breach. For
example:
- If a state grants oil exploration rights in an area claimed by another state, it violates the
latter’s territorial sovereignty.
- If a state builds dams or waterworks that reduce the water flow to another co-riparian state,
it infringes that state’s rights.
In such situations, the proper resolution must include both:
1.
Clarifying or delimiting the rights (distributive justice), and
2.
Stopping the wrongful conduct or awarding compensation (reparative justice).
Finally, a dispute may concern just the entitlement to a right, even before any breach has occurred.
Resolving such disputes in advance, through negotiated agreements, plays a vital role in preventing
future conflicts.
3. Negotiation is the main diplomatic means of settling international disputes under Article 33(1) of
the UN Charter, and it plays a central role in all other peaceful methods of dispute resolution.
On one side, negotiation is closely connected to other diplomatic tools such as:
•
Good offices,
•
Mediation,
•
Enquiry, and
•
Conciliation.
These methods are all intended to facilitate a negotiated solution between the disputing parties.
Even adjudication, often involves negotiation either before or after the judgment, to implement the
result.
On the other side, negotiation is also a precondition for using third-party settlement mechanisms,
such as arbitration or judicial settlement. This is because parties usually need to negotiate a special
agreement in order to submit a dispute to a tribunal. The only exception is when a state has already
consented in advance so that third-party jurisdiction becomes compulsory.
Negotiations about the method of settlement (i.e. procedural negotiations) are not the same as
negotiations about the substance of the dispute. However, in practice, the two are often
intertwined.
49
This point was clearly made by the arbitral tribunal in the 2015 jurisdictional decision in Philippines
v. China. The tribunal noted that:
“Diplomatic communications and exchanges do not divide neatly between procedural and
substantive matters.”
This reflects reality: during a pressing dispute, states rarely keep their communications strictly
separated. Instead, their correspondence about how to resolve the dispute often includes their legal
or political positions on the substantive issues.
Thus, proposals about the means of settlement will often include some discussion of the merits of
the dispute. This is normal and expected in international practice.
In public international law, negotiation is a means to resolve disputes between states. Its main
purpose is to help parties reach an agreement about the dispute. If that fails negotiation should at
least help the parties agree on a third-party means of dispute resolution, such as arbitration or
adjudication.
Importantly, states have a general obligation to negotiate in good faith before turning to
adjudication, when available. This does not mean they must reach an agreement, but rather that
they must genuinely try to do so.
This was clarified by the International Court of Justice (ICJ) in the famous North Sea Continental Shelf
case. The Court emphasized that:
“The Parties are under an obligation to enter into negotiations with a view to arriving at an
agreement (…) and to conduct themselves so that the negotiations are meaningful.”
In other words, negotiation must be sincere, not just a formality. A state cannot claim it has fulfilled
its obligation if it refuses to consider any compromise.
Beyond negotiation, there are other diplomatic means of dispute settlement under Article 33(1) of
the UN Charter, including good offices and mediation.
- Good offices refer to the involvement of a neutral third party who facilitates communication
between the disputing states, without getting involved in the substance of the discussions.
- Mediation involves active engagement by the third party, who relays proposals and helps
the sides find common ground. A mediator might even suggest solutions, adjusting them
according to each side’s feedback.
We have seen real-world examples of this:
1. King Fahd of Saudi Arabia played a good offices role in the 1980s dispute between Qatar and
Bahrain over maritime and territorial claims. He hosted meetings but did not intervene
directly. Eventually, after years of fruitless negotiation, Qatar brought the dispute before the
ICJ in 1991. The ICJ accepted jurisdiction in 1994 and gave a final ruling in 2001.
2. Another important case is the Iran–US crisis in 1979. After Iranian militants seized US
diplomats during the Iranian Revolution, the Algerian Government stepped in. It first acted
through good offices, then shifted into mediation, ultimately brokering a complex
agreement—the Algiers Accords—which resolved the crisis and led to the creation of the
Iran–US Claims Tribunal.
50
Another important tool in peaceful dispute settlement is the commission of inquiry, particularly
useful when a dispute involves technical or scientific issues—for example, in the fields of
engineering, hydrology, or ballistics.
These commissions aim to clarify facts and provide an objective understanding of the technical
aspects of the dispute.
They are usually non-binding, but their findings often serve as a valuable basis for negotiation.
Commissions of inquiry are usually established by agreement between the parties, but some
multilateral treaties provide for their use in advance, typically on an optional basis.
In some cases, the parties may agree to make the commission’s findings binding, giving legal force.
In the context of peaceful dispute settlement, both commissions of inquiry and conciliation
commissions are non-binding, third-party mechanisms used to facilitate negotiations between
disputing states. These mechanisms differ in scope but share the goal of easing tensions through
structured and impartial processes.
A commission of inquiry is typically established by agreement between disputing parties, and it
primarily serves to ascertain the facts of a dispute. Its findings, though non-binding, can serve as an
authoritative basis for subsequent negotiations.
The Permanent Court of Arbitration (PCA) provides administrative and logistical support to such
commissions, either from its headquarters in The Hague or in partner countries.
Conciliation resembles inquiry procedurally but has broader competence: it investigates facts and
considers the legal positions of the parties. A conciliation commission can issue non-binding
proposals for dispute resolution. Like inquiry, conciliation is voluntary and depends on the parties’
agreement.
The PCA offers Optional Conciliation Rules, including specialized rules for disputes involving natural
resources and the environment.
These rules are largely inspired by the UNCITRAL Conciliation Rules, ensuring consistency with
international legal standards.
4. Over the past few decades, international adjudication has witnessed growth, particularly with
increasing recourse by states to international courts and tribunals. This marks a shift from the
situation that prevailed up to the late 1970s, when confidence in international judicial mechanisms
was relatively low.
An illustration of this evolution was offered by Sir Christopher Greenwood, former ICJ judge in a
2020; he described how public international law was considered a marginal field of legal practice,
unlikely to generate cases frequently.
Greenwood noted that in 1977–78, the ICJ had only one case on its docket, and it lacked jurisdiction
to hear it. The ICJ Reports for 1977 were very thin.
This contrasts with the current picture: as of the time this book was going to press, the ICJ had
handled 195 cases since its inception in 1947, illustrating its increasing relevance and activity in
modern international relations.
51
The International Court of Justice (ICJ) exercises two primary forms of jurisdiction:
1. Contentious jurisdiction, based on the consent of the disputing parties, allows the ICJ to
issue binding judgments in legal disputes between states. These judgments are binding only
on the parties to the case, as stated in Article 59 of the ICJ Statute and Article 94 of the UN
Charter.
2. Advisory jurisdiction, under which the Court may issue non-binding legal opinions at the
request of the UN General Assembly, Security Council, or other UN organs on legal questions
related to their functions. Although advisory opinions are not formally binding, they are
considered authoritative interpretations of international law and carry political and legal
weight.
As for the distinction between adjudication and arbitration, the difference is often subtle in interstate disputes. In both cases, jurisdiction and applicable law depend on state consent, and both
serve to administer international justice. Adjudication typically occurs before permanent courts like
the ICJ and the International Tribunal for the Law of the Sea (ITLOS). These bodies have preestablished procedures, unlike arbitration, which is generally ad hoc and more tailored to the
specific dispute at hand.
Under international law, the jurisdiction of the International Court of Justice (ICJ) in contentious
cases is based on state consent. A state may validly object to the Court’s jurisdiction unless it has
previously consented to it through one of three mechanisms:
1. A jurisdictional clause in a treaty governing the dispute;
2. A special agreement between the parties referring a specific dispute to the ICJ;
3. A unilateral declaration under Article 36(2) of the ICJ Statute, whereby a state accepts the
Court’s jurisdiction ipso facto and without further agreement, on condition of reciprocity.
Article 36(2) specifies that states may declare their acceptance of the Court’s jurisdiction in relation
to all legal disputes, including:
•
treaty interpretation,
•
questions of international law,
•
facts constituting a breach of international obligation, and
•
the nature or extent of reparations.
The effect of such declarations is reciprocal: a state can only be brought before the ICJ under this
basis by another state that has also accepted the same jurisdiction.
Currently, about 70 states have in force declarations under Article 36(2) of the ICJ Statute. For
example, Italy filed its declaration in 2014, while the United States withdrew its own in 1985 after
the ICJ upheld jurisdiction in Nicaragua v. United States. Despite that withdrawal, the US can still
appear before the ICJ through treaty-based jurisdictional clauses.
In contrast, the International Tribunal for the Law of the Sea (ITLOS), has a presumptive jurisdiction.
According to Article 287(1) of UNCLOS, parties may choose among dispute settlement mechanisms.
However, if no explicit choice is made, disputes default to Annex VII arbitration.
52
International arbitration in inter-state disputes resembles domestic arbitration, but with two key
differences:
1.
It is based on international agreements, not contracts.
2.
It deals with inter-state rather than individual disputes.
Arbitration can be initiated either:
•
Ad hoc, by a compromis between the disputing parties, or
•
Under a treaty clause, referring future disputes to arbitration.
The evolving landscape of international dispute settlement reveals a growing integration between
adjudicative and non-adjudicative mechanisms, reflecting a shift away from viewing legal
adjudication as a last resort. Instead, international courts and tribunals are now used in parallel with
diplomatic tools, and sometimes even to catalyze negotiations that had stalled.
This complementarity becomes especially visible in two main types of disputes:
(a) Legal disputes embedded in broader political conflicts:
Adjudication through arbitration depoliticized the issue, allowing the tribunal to resolve complex
jurisdictional questions, including claims of immunity, without public compromise. This kind of legal
clarification can support diplomatic de-escalation by removing contentious factual or legal
uncertainties.
(b) Disputes concerning distributive justice:
In such cases, adjudication often sets a legal baseline while encouraging continued diplomatic
engagement.
In the Gabčíkovo–Nagymaros Project case (Hungary/Slovakia), the ICJ issued a detailed legal
judgment on the legality of unilateral actions relating to a joint hydroelectric project. However, the
Court went further, urging the parties to return to negotiations to find a solution that respected
both legal obligations and the cooperative aims of their treaty. This reflects how adjudication can
frame obligations while fostering future cooperation.
From this example, a broader principle emerges—international adjudication is increasingly viewed
as part of a broader toolkit for dispute settlement, rather than a separate or exclusive path. As Sir
Robert Jennings remarked, courts and arbitration panels are now seen as “tools in the course of
diplomatic negotiations”, not isolated forums.
This was reinforced by Stephen Schwebel, who emphasized in 1998 that international litigation can
serve to guide or facilitate political negotiations, often providing clarity, authority, or momentum to
settle disputes before final judgments are even delivered.
While adjudication and diplomacy were once seen as separate approaches, modern practice
demonstrates that they are mutually reinforcing. International courts can provide legal clarity,
depoliticization, and procedural legitimacy, while diplomacy provides flexibility, political buy-in, and
implementation. In a world of increasingly complex inter-state disputes, blending these mechanisms
often offers the most effective path toward peaceful and sustainable outcomes.
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The advisory jurisdiction of the ICJ, as established under Article 65 of the Court’s Statute, is a unique
procedural mechanism whereby the Court is invited to render a legal opinion—not on a dispute
between states, but on legal questions referred to it by certain authorized bodies, chiefly the UN
General Assembly, the Security Council, and specialized agencies of the UN.
However, invoking this jurisdiction requires a highly political and diplomatically complex process,
especially when the subject matter is controversial.
Historically, many advisory opinions have dealt with politically charged or legally unsettled matters.
Some notable examples include:
- UN Membership and Competence of the General Assembly (1948–1950), which were deeply
embedded in Cold War dynamics, especially regarding the Soviet Union’s objections to the
admission of certain Western-aligned states.
- The Status of South West Africa (1950) and Namibia (1971), requested in the context of
decolonization and the illegality of South Africa’s continued presence under the apartheid
regime. These opinions supported the legal standing of self-determination and delegitimized
colonial-era claims.
Importantly, although ICJ advisory opinions are non-binding, they carry substantial legal and moral
authority. They are often regarded as authoritative statements of the law and play a crucial role in
shaping international legal discourse.
States that act contrary to well-reasoned advisory findings often face legal, political, and
reputational costs. This persuasive effect is part of the broader normative impact of the ICJ, even
outside the realm of contentious jurisdiction.
The ICJ’s advisory jurisdiction is an essential tool in the international legal order. Though formally
non-binding, advisory opinions carry immense weight due to their substantive authority, procedural
legitimacy, and moral influence. Their effectiveness lies in their ability to reconcile law and politics,
offering legal clarity while supporting broader international consensus and governance.
5. Traditional inter-state adjudication was shaped by the bilateral nature of legal obligations, rooted
in reciprocity. Under this model, international rules created legal relationships where obligations
were owed between individual states, and violations triggered responsibility only toward directly
affected states.
Examples of such bilateral obligations include:
•
Inviolability of diplomatic premises,
•
Jurisdictional immunities,
•
Treatment of aliens, and
•
Freedom of navigation on the high seas.
A breach of these rules typically led to a dispute between the violating state and the specific injured
state. This is consistent with the law of state responsibility, where the injured state may:
1. Assess the violation of its legal rights and the breach of the corresponding obligation,
2. Invoke the responsibility of the wrongdoer uti singuli—individually and directly.
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Since World War II, the landscape of international law has shifted. A growing body of norms now
protect collective interests—either:
•
The rights of all states parties to a multilateral treaty (erga omnes partes), or
•
The interests of the international community as a whole (erga omnes).
Violations of such norms may give rise to international disputes even if no state is individually
affected in the traditional sense.
Thus, the modern framework of inter-state adjudication increasingly accommodates claims based
on collective rights, marking a significant evolution beyond the historical reciprocity-based model.
When a state breaches an obligation owed to all states parties to a treaty or to the international
community as a whole, this constitutes a breach of a collective right. Accordingly, any state may
invoke the international responsibility of the wrongdoing state uti universi, that is:
- On behalf of all treaty parties,
- On behalf of the entire international community, depending on the nature of the obligation.
This includes the right to:
•
Hold the violator accountable, and
•
Seek reparation, particularly for the benefit of those states directly affected.
However, many states may lack the political motivation to act unless they are materially impacted.
This helps explain why traditional bilateral adjudication mechanisms are increasingly supplemented
or replaced by new institutional and procedural models designed to address collective interests.
These alternative mechanisms include:
 The UN General Assembly and Security Council, which may take up or mediate disputes
involving community interests;
 Expert compliance review mechanisms, especially prevalent in human rights and
environmental law, where enforcement does not rely solely on state-to-state litigation but
often involves monitoring bodies, reporting systems, and quasi-judicial organs.
These developments reflect a broader shift in international dispute settlement, whereby
mechanisms are designed not only to address direct harm, but also to protect the systemic integrity
of the legal order and the interests of the global community.
Before turning to institutional mechanisms, it’s important to note a key shift in contentious litigation
before the ICJ, particularly in cases that seek to protect collective interests rather than just bilateral
state rights. As of now, five major cases are pending before the ICJ that reflect this trend. The most
prominent example is:
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1. The Gambia v. Myanmar (2019) – the Rohingya Genocide case
The Gambia brought proceedings under Article IX of the Genocide Convention, claiming that
Myanmar committed acts of genocide against the Rohingya. Crucially, The Gambia was not directly
affected, but invoked its standing based on the erga omnes partes nature of obligations under the
Genocide Convention.
The ICJ affirmed prima facie jurisdiction, rejecting Myanmar’s challenge to The Gambia’s standing.
The ICJ confirmed this view in its judgment on preliminary objections, holding that any state party
can invoke the responsibility of another state party to the Convention.
Now, the Court recognizes that collective values and obligations can create locus standi for all states
parties, as they serve a shared legal interest.
The case has since advanced to the intervention phase, with six Western states and the Maldives
submitting declarations of intervention in November 2023—further underscoring the case’s global
significance.
This case signals a transformative moment in the Court’s approach to collective enforcement,
marking a departure from a strictly bilateral model toward one that accommodates universal values,
particularly in human rights and humanitarian law contexts.
2. Ukraine v. Russian Federation (2022) – Genocide Convention: Reverse Compliance
Ukraine brought it under Article IX of the Genocide Convention to affirm its own compliance.
Ukraine asked the ICJ to:
(a) Declare that it did not commit genocide in Donetsk and Luhansk (contrary to Russian claims),
(b) Hold that Russia’s use of force, justified under the pretext of preventing genocide, violates the
Genocide Convention.
This is an example of a reverse compliance dispute, where a state seeks declaratory relief to disprove
allegations of international wrongdoing, and to challenge the legality of another state’s actions that
are based on such allegations.
Although Russia boycotted the provisional measures phase, it filed preliminary objections in
October 2022. Meanwhile, 32 states submitted declarations of intervention under Article 63 of the
ICJ Statute, underscoring the collective interest in genocide prevention.
On 2 February 2024, the ICJ issued its preliminary objections judgment. It upheld jurisdiction only
with respect to Ukraine’s request for a declaration of compliance under the Genocide Convention.
3. Canada and the Netherlands v. Syria (2023) – Convention Against Torture
Filed on 8 June 2023, this case invokes erga omnes partes obligations under the 1984 Convention
Against Torture. It concerns Syria’s alleged systematic use of torture, particularly during its civil
conflict.
In its order on provisional measures, the Court confirmed prima facie jurisdiction, again reaffirming
the principle that:
“Any State party to the Convention against Torture may invoke the responsibility of another State
party… to bring that failure to an end.”
The case illustrates how states not directly injured can initiate proceedings to enforce collective
treaty norms.
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The fourth case is South Africa v. Israel (filed December 2023), again under the Genocide
Convention. The ICJ upheld its prima facie jurisdiction following a January 2024 hearing. Notably,
South Africa’s locus standi was undisputed, reaffirming that even non-injured states may bring
claims concerning collective rights. However, the Court exercised caution in assessing whether the
facts met the threshold of genocidal intent at the provisional stage.
The fifth and most recent case is Nicaragua v. Germany (March 2024), which accuses Germany of
complicity in alleged genocide and IHL violations in Gaza. This contentious proceeding follows an
advisory opinion requested by the UN General Assembly in 2022. In that opinion—delivered in July
2024—the ICJ found Israel’s occupation and settlement activity since 1967 to violate international
law and held that compensation was owed to the Palestinian people.
5.1 The United Nations was established to maintain international peace and security, as reflected in
Article 1(1) of the UN Charter. A central means to achieve this goal is through the peaceful
settlement of disputes that might endanger peace, a principle embodied in Chapter VI of the
Charter.
Under Chapter VI, both the General Assembly and the Security Council have the authority to make
non-binding recommendations on how disputes may be settled, either upon a state’s request or
motu proprio.  This mechanism relies on the consent of the parties involved and is rooted in
diplomacy.
Chapter VII, however, allows the Security Council to take enforcement action in response to threats
to peace or acts of aggression. Two types of measures are authorized:
1. Non-forcible measures under Article 41—such as economic sanctions or diplomatic
restrictions.
2. Forcible measures under Article 42—such as the use of military force, but only if non-forcible
measures prove inadequate.
Crucially, any enforcement action under Chapter VII must be authorized through a Security Council
resolution, which requires at least 9 affirmative votes and no veto from the five Permanent
Members. This veto power gives each P5 state the ability to block any substantive resolution, often
limiting the Council’s ability to act decisively in politically sensitive crises.
Thus, while the UN framework provides both peaceful and coercive tools for dispute settlement,
the political dynamics of the Security Council remain a defining constraint on the UN’s enforcement
capacity.
The effectiveness of the UN Security Council during the Cold War was hampered by the veto power
of the Permanent Members, particularly due to East-West rivalry between NATO and the Warsaw
Pact, and the intensifying North-South divide amid decolonization. These structural limitations
meant the Council was often paralyzed in addressing threats to peace.
In this context, the General Assembly emerged by diffusing tensions and reaffirming the legal
foundations of the post-war order, albeit without enforcement powers. It provided a space for
restating, reviewing, and redefining international legal principles.
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A key moment in this normative evolution was GA Resolution 2625 (XXV) of 1970, the Declaration
on Friendly Relations, which codified key principles of the UN Charter. Negotiated among three
ideological blocs—Western states, the Socialist bloc, and developing countries—it stands as a
testament to international law as a shared language capable of promoting peaceful coexistence and
cooperation even amid ideological division.
However, in today’s multipolar and fragmented international landscape, where unilateralism and
nationalism are on the rise, this consensus-based approach to the international rule of law is under
strain. While the need for reaffirmation of legal principles remains acute, the current political
climate makes such reaffirmation more difficult, raising concerns about the resilience of law.
The post-Cold War era saw a revitalization of the UN Security Council’s role as originally envisaged
in the Charter, particularly in its swift and unanimous response to the Iraqi invasion of Kuwait in
1990, and again following the 9/11 terrorist attacks in 2001.
However, this renewed cohesion began to deteriorate with tensions over Kosovo’s independence
and worsened during the 2014 Crimea crisis. The 2022 Russian invasion of Ukraine has since dealt a
blow to institutional multilateralism, underscoring the paradox that international institutions are
becoming weaker just as global threats are multiplying.
Against this backdrop, the role of the General Assembly in dispute settlement has gained renewed
attention. Under Article 14 of the UN Charter, the Assembly is empowered to make
recommendations aimed at promoting peace and resolving disputes. However, Article 12 limits this
authority when the Security Council is actively seized of a matter, to prevent conflicting actions and
maintain the Council’s primary responsibility for peace and security.
The Uniting for Peace mechanism, emerged during the Korean War after the Soviet Union vetoed
Security Council action. It empowered the General Assembly to make recommendations, including
on enforcement measures, when the Security Council is paralyzed by a veto.
Although initially controversial and later underused even by its Western sponsors, the doctrine has
seen a revival in the context of the Ukraine crisis. Following Russia’s invasion of Ukraine in February
2022, and its veto blocking Security Council action, the Council adopted Resolution 2623, triggering
an emergency special session of the General Assembly.
This marked the first formal invocation of the Uniting for Peace rationale in decades. A key feature
of the contemporary practice is that Permanent Members using their veto are now given priority
speaking rights in the General Assembly during such sessions. This serves both to uphold the
principle of accountability and to provide the vetoing state an opportunity to explain its position
before the wider UN membership.
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5.2.1 Solidarity obligations in international law—such as those prohibiting torture or genocide—are
owed erga omnes (to all) or erga omnes partes (to all treaty parties). This means that any state can
invoke responsibility for a breach, even if it has no direct material interest at stake.
These obligations are typical of human rights treaties and customary international law, but a major
practical limitation is that states may lack political interest to act if their own nationals or interests
aren’t affected. This is why regional human rights courts exist (e.g., ECtHR, IACtHR), allowing
individuals to seek redress directly, since no universal human rights court exists.
At the universal level, treaty bodies composed of independent experts monitor compliance, except
for the UN Human Rights Council, which is state-driven. These bodies use various compliance tools:
periodic state reporting, site inspections, and individual communications (if states recognize their
competence).
A good example is the Committee Against Torture (CAT), created under the 1984 UN Convention
Against Torture. It:
 Reviews periodic reports from states,
 Can initiate confidential inquiries into systematic torture,
 Handles state-to-state complaints, and
 Acts as a quasi-judicial body when authorized to receive individual complaints.
5.2.2 One major reason why states may fail to comply with international environmental law—
especially Multilateral Environmental Agreements (MEAs)—is that fulfilling these obligations often
requires high scientific, technological or financial capacity. These obligations are typically owed to
the community of states parties, not to specific injured states.
To address potential non-compliance, MEAs often set up compliance review mechanisms, which are
non-adversarial, permanent, and preventive. Unlike traditional dispute settlement methods, these
bodies aim to assist states in fulfilling complex obligations.
Such mechanisms:
- Resemble inquiry or conciliation processes,
- May be triggered by the state itself facing difficulties (self-trigger, though rare),
- Often work alongside regular reporting systems (e.g., biennial reports),
- Can act proprio motu (on their own initiative) based on reports or external information,
- Accept public communications, especially where individuals are direct beneficiaries.
A key example is the 1998 Aarhus Convention, which grants public rights to environmental
information, participation, and justice. Its compliance mechanism can be triggered by the public.
Typically, these mechanisms issue recommendations rather than binding decisions. These
recommendations are often directed to the Conference of the Parties (CoP/MoP) and may include:
•
Technical, scientific, legal, administrative, or financial advice,
•
Cautions,
•
Or even suspension of rights under the treaty.
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In more serious cases, the process may result in “naming and shaming”, relying on public exposure
to encourage compliance. However, the effectiveness of such mechanisms depends on the value
states place on their reputation and legitimacy.
Regrettably, the growing trend toward nationalistic unilateralism suggests that reputational
concerns are becoming less influential, both internationally and domestically, thereby challenging
the effectiveness of these mechanisms.
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CHAPTER 7
1. The international legal system is quite different from domestic legal systems. While states usually
organize their legal systems in a centralized, hierarchical, and compulsory way, the international
system is more fragmented. Law-making is participatory, adjudication depends on state consent,
and enforcement is largely decentralized.
One major exception is the UN Security Council, which can take enforcement action when the major
powers agree—but such consensus has become very rare, especially since the Ukraine crisis.
Some of the key areas of substantive international law.
1. Use of Force and Armed Conflict: First, we discuss the prohibition on the use of force—
known as jus ad bellum—as well as the rules that govern how war is conducted, called jus in
bello or international humanitarian law.
2. International Criminal Law: focusing on the so-called “core crimes,” such as genocide, war
crimes, and crimes against humanity.
3. International Economic Law: international investment and trade law, which regulate
economic relations between states and with private actors.
4. Law of the Sea: how it has moved from a simple focus on navigation to a more complex
system of maritime zones and state jurisdiction.
5. International Human Rights Law: This area has grown significantly since World War II. It
challenges the old idea that states can do whatever they want within their borders without
international scrutiny.
6. Migration and Migrant Rights: legal rules governing migration, which are spread across
different branches of international law, including human rights and the law of the sea.
7. International Environmental Law: special principles and unique mechanisms for creating and
implementing environmental norms, reflecting the global nature of environmental
problems.
8. Jurisdictional Immunities law on immunities for states, international organizations, and their
officials. This includes debates about how immunities can limit victims’ access to justice.
2.1 Until the early 20th century, the use or threat of force was widely accepted as a lawful way of
resolving international disputes, reflecting a system based on nearly unlimited free competition.
The first steps towards restricting this practice started with the 1907 Hague Convention on the
limitation of force for the recovery of contract debts. This treaty was a response to the incident in
Venezuela, where Germany, Italy, and the UK imposed a naval blockade to collect unpaid sovereign
debts. The convention marked the first visible attempt to limit military force in such contexts.
It was only after the First World War, that the international community began to consider a ban on
the use of force. This was reflected in the Covenant of the League of Nations, the predecessor of
the United Nations. Under Article 11 of the Covenant, war and its threat were declared matters of
concern for the entire League. Meanwhile, Article 12 imposed an obligation not to go to war with
another League member unless they had first tried peaceful dispute settlement. Even then, they
had to wait three months after a judgment or award was ignored before taking further action.
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Despite its forward-looking nature, this framework had three key limitations:
(a) Limited applicability: Because the Covenant was new and not yet customary international
law, it only bound states that were parties to it.
(b) Narrow scope: The prohibition applied to “war”, which allowed states to use other forms of
military force without formally declaring war, thus circumventing the ban.
(c) Conditional prohibition: Article 12 didn’t impose an outright ban on force. It merely delayed
its use until after peaceful methods had failed and a waiting period had passed. It still
allowed unilateral force as a means of enforcing judgments.
The shortcomings of the League of Nations’ Covenant in limiting the use of force were addressed
over time. A key development was the broadening of international treaty practice, which included
states that hadn’t joined the League, thus helping to build customary international law.
Kellogg-Briand Pact of 1928, signed by France, Germany, and the United States  This treaty
condemned war as a tool for resolving disputes and by renouncing it as an instrument of national
policy.
This effort was reinforced in 1933 by the Montevideo Convention on the Rights and Duties of States,
adopted within the Organization of American States framework. This Convention banned aggressive
wars and introduced the principle of non-recognition of any territorial gain achieved through force.
What’s important for the formation of customary law is that both conventions involved the United
States, which had never joined the League of Nations. President Warren G. Harding led the U.S.
toward a more isolationist approach, and the U.S. Senate blocked membership in the League.
These treaties were crucial in shaping international legal opinion across different world regions. This
widespread state practice helped crystallize a customary ban on the use of force, even before the
Second World War began.
This legal foundation was used by the Nuremberg and Tokyo Tribunals, which prosecuted German
and Japanese leaders for the crime of aggression—marking a development in the enforcement of
the prohibition on the use of force.
Before the Second World War, both state practice and opinio juris increasingly pointed toward a
growing consensus against the use of force. A notable example is the Kellogg-Briand Pact, which was
cited in diplomatic condemnations of acts of aggression.
Similarly, the Montevideo Convention of 1933 was seen as a “living instrument.” In the 1986 Nicaragua v. United States
case, the International Court of Justice (ICJ) specifically recognized U.S. support for that Convention—and its earlier
endorsement of a 1928 resolution condemning aggression—as evidence of American opinio juris supporting the
prohibition of the use of force.
Article 2(4), states: “All Members shall refrain in their international relations from the threat or use
of force against the territorial integrity or political independence of any state, or in any other manner
inconsistent with the purposes of the United Nations.”
This article does not limit the ban to formal declarations of war. In fact, the phrase “territorial
integrity or political independence,” was meant to reinforce the prohibition—not restrict it.
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The ICJ, in the Nicaragua case, confirmed that Article 2(4) reflects customary international law. The
Court emphasized that this principle is frequently cited by states as binding treaty law and as a
“fundamental” or “cardinal” rule of customary law.
The Court also highlighted the importance of the 1970 UN General Assembly “Friendly Relations”
Resolution (Resolution 2625). According to the Court, states’ support for such resolutions shows
agreement with the Charter, but also acceptance of the rules stated in the resolution as customary
law.
Finally, the scope of the prohibition on the use of force includes more than just open aggression. In
the same Nicaragua judgment, the Court found that the U.S., by financing and arming irregular
forces, had violated the ban. The Court cited the Friendly Relations Resolution, which provides that:
“Every State has the duty to refrain from organizing or encouraging the organization of irregular
forces or armed bands, including mercenaries, for incursion into the territory of another State.”
This confirms that indirect uses of force, such as supporting insurgents or armed groups, also fall
under the prohibition of Article 2(4) and are customary international law.
2.2 Article 51 of the UN Charter recognizes the right of self-defense in the event of an armed attack.
This right may be exercised individually or collectively, by other states acting in support, but only
until the UN Security Council takes measures to maintain or restore international peace.
Any action taken in self-defense must be immediately reported to the Security Council, and it does
not override the Council’s primary authority to act.
The right to collective self-defence requires the consent of the state that has been attacked.
An example of this was in 1990, when Iraq invaded Kuwait. Kuwait requested help from the United States and its allies,
and, unusually, the Security Council managed to reach consensus—despite the usual tensions among the five
permanent members (P5)—and authorized the intervention.
A notable example of pre-agreed self-defence is found in Article 5 of the Washington Treaty of 1948,
which created NATO. According to this, an armed attack against any NATO member in Europe or
North America is considered an attack against all members. Each party agrees to assist the state
attacked, including using armed force, in accordance with Article 51 of the UN Charter.
This demonstrates how collective self-defence can be institutionalized through treaties and
anticipated in advance, while still conforming to the rules of the UN Charter.
Article 51 of the UN Charter allows for an exception to the prohibition of the use of force. This is
why self-defence is considered a circumstance precluding wrongfulness. It is an exceptional and
justifying legal response to an armed attack.
The use of the term “inherent right” in Article 51 reflects the customary nature of the right to selfdefence. It shows that the Charter is incorporating customary international law by reference.
However, this brings with it the difficulties of interpreting unwritten rules.
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Article 51 also states that self-defence is permitted “until the Security Council has taken measures”.
This implies that:
 The right to self-defence is temporary, lasting only until the threat is repelled or the Council
takes action.
 The Security Council has the primary authority to assess whether self-defence is being
lawfully exercised. However, this system often fails due to the veto power of the Permanent
Members (P5).
For instance, the Security Council could not assess the legality of Russia’s actions in Ukraine due to
Russia’s veto.
Though the ICJ is not the primary organ for judging self-defence, it can still play a role indirectly. For
example, in 2023, South Africa brought a case against Israel to the ICJ, alleging acts of genocide
during military operations in Gaza. While the ICJ is not ruling directly on the legality of self-defence,
if it finds genocidal acts occurred, this will imply a clear violation of the proportionality requirement.
Finally, violations of self-defence limits may result in state responsibility and even individual criminal
liability, as seen with the arrest warrants issued by international bodies in November 2024 for top
Israeli officials.
2.3 While self-defence is a recognized exception to the prohibition on the use of force under
customary international law and Article 51 of the UN Charter, the doctrine of humanitarian
intervention remains highly controversial.
One of the most well-known cases of humanitarian intervention occurred in 1999, when NATO launched a military
campaign against the Federal Republic of Yugoslavia, citing the need to stop human rights abuses against ethnic
Albanians in Kosovo. NATO members argued that the intervention was justified as it aligned with the purposes of the
UN Charter.
However, this legal reasoning was disputed. Russia, backed by China and Namibia, proposed a draft resolution in the
UN Security Council to condemn the NATO action, but the resolution was rejected by 12 votes. Interestingly, Russia’s
condemnation stands in contrast to the similar legal arguments it used later to justify its 2022 invasion of Ukraine,
claiming it was protecting populations at risk—a claim widely rejected by the international community.
So far, the International Court of Justice (ICJ) has not ruled on whether humanitarian intervention
is a valid exception to the prohibition of the use of force under Article 2(4). One reason may be the
cautious approach of states before the Court. States are often reluctant to make legal statements
about humanitarian intervention, possibly because they want to preserve the option of invoking it.
However, Ukraine took a more direct legal approach in 2022 against Russia at the ICJ. It argued that Russia had violated
the Genocide Convention by abusing it as a pretext for its military invasion. Ukraine requested that the Court assess the
lawfulness of Russia’s use of force as incidental.
In response the ICJ noted that even if military action is taken to prevent or punish genocide, it must still comply with
the principles of the UN Charter.
However, in its 2024 judgment on preliminary objections, the Court ruled that it did not have jurisdiction to decide
whether Russia’s use of force was illegal under the Genocide Convention. The Court clarified that even if Russia’s actions
violated international law, they would breach the rules on the use of force and state recognition, not the Genocide
Convention itself.
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Thus, the legality of humanitarian intervention remains unresolved in international jurisprudence.
The ICJ has emphasized that any military action, even if purportedly humanitarian, must conform to
the Charter’s core principles, especially the ban on force.
2.4.1 While the UN Charter establishes a general prohibition on the use of force, an exception lies in
the authorization by the UN Security Council under Chapter VII. This pathway to the legitimate use
of force is political and depends on the cohesion among the five permanent members (P5).
A notable example of successful Security Council action occurred during the Iraq-Kuwait crisis in 1990–1991. The end of
the Cold War had just created a window of international consensus, especially with the newly established Russian
Federation seeking Western support. This led the Security Council to pass a series of resolutions:
1. Resolution 660 (1990) condemned Iraq’s invasion and demanded withdrawal.
2. Follow-up resolutions imposed economic and political sanctions.
3. In Resolution 678 (1990), the Council authorized Member States to use “all necessary means” if Iraq failed to
comply by January 1991 — effectively authorizing military intervention.
Importantly, Resolution 678 also reaffirmed the inherent right to self-defence under Article 51, indicating that collective
security and self-defence can be complementary.
However, the UN Charter does not authorize the Security Council to delegate the use of force to
states. Instead, it envisions that the Council would maintain a military force (Article 43), which has
never been implemented due to Cold War political realities. As a result, the Council developed the
practice of delegating enforcement actions to coalitions of willing Member States.
This divergence from the Charter’s original design also led to the emergence of peacekeeping
operations (blue helmets), which:
•
Do not involve force, except in self-defence,
•
Are lightly armed,
•
Are deployed with consent of the host state(s),
•
Serve monitoring, buffer, and humanitarian functions, not enforcement.
In contrast, enforcement operations involving use of force are carried out by states upon explicit
Security Council authorization, often in conjunction with self-defence claims.
For example, after 9/11, the Security Council authorized force against Afghanistan, not because it had directly attacked
the US, but because it harbored Al-Qaeda, the group responsible for the attacks. This reflected an evolution in Council
practice toward recognizing state responsibility for non-state actors within their territory.
However, this practice has been inconsistent. Since the resurgence of geopolitical divisions among
the P5 from the late 2000s onward, the Security Council has again become paralyzed, unable to:
•
Determine whether conditions for self-defence exist,
•
Authorize force where necessary,
•
Respond effectively to emerging security threats.
Thus, while Security Council authorization remains a cornerstone of collective security, its
effectiveness is limited by political will, particularly P5 unanimity, and constrained by the original
design of the Charter, which envisioned a centralized UN force that was never realized.
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2.4.2 Early in the UN’s history, the Security Council was already facing paralysis due to the veto
power, particularly by the USSR.
A key example of this occurred during the Korean War in 1950. In response, the Western powers proposed an alternative
mechanism:
- If the Security Council is blocked by a veto in the face of a threat to international peace and security, the General
Assembly may act to address the situation.
- Adoption of the “Uniting for Peace” resolution, which was used to authorize action in Korea.
This mechanism amounted to an unwritten constitutional modification of the UN Charter. It did not
evolve into customary international law because:
•
It was strongly opposed by the USSR and its allies.
•
The Western states later abandoned the idea once they lost voting dominance.
However, the principle was revived in 2022, when the General Assembly adopted Resolution 2623
in response to Russia’s veto blocking Security Council action at the start of its military invasion of
Ukraine.
The ICJ can, in theory, exercise jurisdiction over issues related to use of force and self-defence, but
such cases are rare due to:
•
The consensual nature of ICJ jurisdiction,
•
The reluctance of powerful states to submit disputes involving their national security.
These states have long held the view that decisions on the use of force are political, and therefore
within the exclusive competence of the Security Council, not the Court.
An example of the Court’s jurisdictional restraint is seen in its 2024 ruling in the Ukraine v. Russia Genocide Convention
case. The Court:
 Declined jurisdiction over Ukraine’s claim regarding the wrongfulness of Russia’s use of force, stating that such
matters fall outside the scope of the Genocide Convention.
 This shows the Court’s cautious approach to addressing the legality of force even when it appears as an
incidental issue.
The ICJ may still issue provisional measures under Article 41 of its Statute:
- aim to preserve the rights of the parties pending the Court’s final judgment.
- The Court must notify the Security Council and the parties after issuing such measures.
- This tool has been used, for example, in the South Africa v. Israel genocide case, where the
Court ordered provisional measures to prevent possible genocidal acts.
Can the ICJ order provisional measures that limit or suspend a state’s claimed right to self-defence
under Article 51 of the UN Charter?
1) Article 92 of the UN Charter affirms that the ICJ Statute is part of the Charter itself.
2) Consequently, the ICJ’s actions must be in harmony with the Charter, including Article 51,
which affirms the right to individual or collective self-defence if an armed attack occurs.
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In its Order of 16 March 2022, the ICJ: Ordered Russia to suspend its military operations in Ukraine and Directed Russia
to ensure that no supported armed groups continue military actions. This order was based on the Court’s prima facie
jurisdiction under the Genocide Convention, and although it did not directly judge the legality of the use of force, the
substance of the measures clearly challenged the validity of Russia’s claim to self-defence.
The ICJ appeared to base its order on the implicit assessment that Russia’s use of force could not be
justified under self-defence, since:
•
No armed attack had occurred against Russia from Ukraine.
•
Therefore, the invocation of Article 51 by Russia was abusive.
Although the Court, in its 2024 judgment on preliminary objections, declined jurisdiction to rule on
the lawfulness of the use of force under the Genocide Convention, this does not negate the legal
and factual implications of its earlier provisional measures order.
If the ICJ does not reverse its stance in the final judgment:
- Russia’s non-compliance with the provisional measures may constitute an international
wrongful act.
- This could form the legal basis for compensation to Ukraine, if such reparation is requested
during the merits phase.
- Such a request would not violate procedural.
- It would fit within the procedural continuity of the Court’s binding decisions in the case.
1. South Africa v. Israel: Provisional Measures (January 2024)
The ICJ in South Africa v. Israel (Order of 26 January 2024):
- Did not order a ceasefire, despite South Africa’s request.
- This omission can be interpreted as recognition of Israel’s right to self-defence under Article
51, following the Hamas attack of 7 October 2023.
However, the Court:
- Imposed specific obligations on Israel regarding the conduct of its military operations.
- Ordered Israel to prevent acts in breach of the Genocide Convention and to ensure the
provision of basic services and humanitarian aid to Palestinians in Gaza.
This indicates that while self-defence may be legitimate, it remains subject to legal constraints,
particularly proportionality and respect for humanitarian law.
Beyond contentious cases, the ICJ can issue advisory opinions on legal issues relating the use of
force. Examples include:
 Legality of the Threat or Use of Nuclear Weapons (1996)
 Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory (2004)
 Legal Consequences arising from the Policies and Practices of Israel in the Occupied
Palestinian Territory (ongoing)
These opinions are not legally binding, but they carry legal weight due to the Court’s authoritative
standing and the legal expertise of its judges. They are often used to clarify international law, guide
state behavior, and influence legal and political debates.
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2.5 International Humanitarian Law (IHL), also known as jus in bello, is the branch of international
law that governs the conduct of hostilities during armed conflict. Its main aim is to limit the effects
of war by protecting persons not participating in hostilities—such as civilians, the wounded, and
prisoners—and by regulating the means and methods of warfare. It seeks a balance between military
necessity and humanity.
A key principle is distinction, which prohibits direct attacks against civilians and civilian objects.
Harm to civilians, while sometimes unavoidable, must never be excessive in relation to the
anticipated military advantage.
IHL applies to all armed conflicts, whether international or non-international, and binds all parties,
including non-state armed groups. According to the International Criminal Tribunal for the former
Yugoslavia (ICTY), armed conflict exists whenever there is sustained armed violence between
organized actors or between states.
Though the ethical limits of warfare have been discussed since ancient times, modern IHL emerged
in the 19th century. The 1859 Battle of Solferino inspired Henry Dunant to found the International
Committee of the Red Cross (ICRC). In 1863, Francis Lieber drafted the Lieber Code in the U.S., an
early military code of conduct. These developments laid the groundwork for the Hague Conventions
(1899 and 1907), which codified rules on warfare and introduced the Martens Clause, ensuring
humanitarian protections even in legal gaps.
A turning point came with the 1949 Geneva Conventions, which remain the foundation of IHL today.
They protect:
1. the wounded and sick on land,
2. the shipwrecked at sea,
3. prisoners of war, and
4. civilians during armed conflict.
Article 3 applies to non-international conflicts and establishes basic humane treatment standards.
The 1977 Additional Protocols expanded protections, particularly in non-international conflicts.
However, since not all states have ratified these protocols, it’s often necessary to assess whether
certain rules are part of customary international law.
Three core principles of IHL are:
 Distinction: between combatants and civilians, and between military and civilian objects.
 Military necessity: allows force only to achieve legitimate military aims not forbidden by law.
 Proportionality: prohibits attacks if civilian harm would be excessive relative to the expected
military gain.
They collectively uphold the humanitarian purpose of IHL: to reduce suffering in war.
Legitimate combatants—those entitled to prisoner-of-war status—must:
1. belong to an organized armed force or group,
2. follow a command structure,
3. distinguish themselves from civilians (e.g., by uniform or visible weapons), and
4. comply with IHL.
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While IHL applies only during armed conflict, international human rights law (IHRL) applies at all
times, including during war. Some rights, like freedom of movement, may be lawfully restricted in
wartime, but core rights—such as the right to life and the prohibition of torture—remain nonderogable. Despite different scopes, IHL and IHRL are complementary and must be interpreted
consistently to maximize the protection of human dignity.
Finally, IHL imposes obligations on both states and individuals. States are internationally responsible
for violations committed by their armed forces, while individuals may be held criminally responsible
for war crimes. This dual system of accountability ensures that breaches of humanitarian norms do
not go unpunished and reinforces the legal and moral framework that governs warfare.
3. Traditionally, international law addresses States, holding them responsible for wrongful acts
carried out by their organs. However, in cases of serious breaches—like genocide, aggression, or
violations of international humanitarian law (IHL)—both state and individual responsibility may
arise. While states are accountable for the actions of their officials, individuals, including leaders and
commanders, can also be criminally prosecuted.
This dual responsibility is affirmed by Article 58 of the ILC’s Articles on State Responsibility, which
clarifies that holding a state accountable does not preclude individual liability. The International
Court of Justice (ICJ) confirmed this distinction in the 2007 Bosnia v. Serbia case, stating that acts
like genocide and complicity in genocide can trigger both state and individual responsibility.
International criminal law focuses directly on individuals, not states. The core crimes are:
- Genocide
- Crimes against humanity
- War crimes
- Crime of aggression
These crimes incur personal criminal liability, regardless of whether the state is also responsible. A
person may be acquitted of a crime even if their state is found to have violated international law,
and vice versa.
An example is the Srebrenica massacre (1995): Serbian officials were convicted of genocide by the ICTY, but the ICJ ruled
Serbia was not directly responsible for committing genocide, only for failing to prevent and punish it.
Core crimes are subject to universal jurisdiction—any state can prosecute them, even without
territorial or national links, because they offend the international community as a whole. States must
either:
1. Prosecute the suspect,
2. Extradite them to a competent court (known as aut dedere, aut judicare).
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Post-WWII Tribunals (Nuremberg & Tokyo) defined core crimes but were limited in scope and legal
authority. The UN Genocide Convention (1948) marked the first treaty imposing universal duties to
prevent and punish genocide. Cold War tensions delayed efforts, especially regarding the definition
of aggression. In the 1990s, the ICTY (1993) and ICTR (1994) were created. These developments led
to the Rome Statute (1998) and the creation of the International Criminal Court (ICC), the first
permanent court with jurisdiction over all four core crimes.
The Rome Statute outlines the ICC’s structure, jurisdiction, and procedures. The ICC exercises
complementary jurisdiction—it acts only when national courts are unwilling or unable to prosecute.
A definition of the crime of aggression was adopted in 2010, but the inclusion of crimes like terrorism
remains unresolved. Major powers such as China, India, Russia, and the United States have not
ratified the Rome Statute, limiting the ICC’s global reach.
4.1 International Investment Law (IIL) aims to protect foreign investors from arbitrary or
discriminatory actions by host states, while also promoting economic development, especially in
strategic sectors like infrastructure, energy, and public utilities.
Although IIL has roots in customary international law, it is mainly shaped by Bilateral Investment
Treaties (BITs) and Free Trade Agreements (FTAs). Core principles include:
1) Fair and Equitable Treatment (FET): prohibits arbitrary or discriminatory conduct and upholds
the investor’s legitimate expectations.
2) Full Protection and Security (FPS): obliges the host state to shield investors from physical or
legal harm.
3) Protection against unlawful expropriation: lawful only for a public purpose, nondiscriminatory, and with prompt, adequate, and effective compensation (Hull formula).
Modern treaties recognize the right of states to regulate in the public interest (e.g. health,
environment, human rights). Some regulatory actions that reduce investment value may not require
compensation if taken in good faith for legitimate purposes.
There is ongoing debate over whether this reflects a new customary rule or a principle of
proportionality in IIL.
To be protected under IIL, an investment must be substantive, long-term, and involve commercial
risk. While purely financial investments like bonds were traditionally excluded, some arbitration
tribunals have extended protection to them, though inconsistently.
Investor nationality is typically based on incorporation or business seat, without examining actual
shareholders. This has enabled nationality planning, where companies structure themselves to
benefit from favorable treaties.
IIL fits within broader international law, particularly treaty law and the law of state responsibility.
The current form of IIL took shape after the Cold War, when many countries liberalized their
economies, privatized industries, and opened to foreign investment. A key development was
allowing foreign investors to sue states directly via international arbitration.
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ISDS systems have faced criticism, especially from Latin American countries like Bolivia, Ecuador, and
Venezuela, which withdrew from several treaties. Others, like Brazil and Indonesia, have also moved
away from traditional BITs. Still, sunset clauses in many treaties extend protections for years after
withdrawal.
Developed countries, including EU members, have also raised concerns. The EU has worked to phase
out arbitration within its legal system, preferring disputes to be resolved in domestic courts with
oversight from the CJEU.
The shift in attitudes reflects a “pendulum effect” between investor protection and state
sovereignty. Many countries have adopted new BITs emphasizing public interest (health,
environment, human rights).
Arbitration institutions such as ICSID and UNCITRAL have introduced reforms to enhance
transparency (e.g. third-party participation), allow counterclaims by states, and ensure more
balanced proceedings.
These trends suggest a more balanced investment law framework, combining investor protection
with respect for state regulatory powers.
4.2 Another development in international investment law is the increasing sensitivity of arbitral
tribunals to public interest concerns, particularly through the evolving case-law. Even in the absence
of explicit treaty provisions, tribunals have employed interpretation methods to integrate
environmental and other public interest considerations into their decisions.
This evolution is well illustrated by comparing two cases involving Costa Rica as the respondent state, which show a
significant shift in arbitral reasoning over an 18-year span. In the 2000 Santa Elena case, the tribunal ruled that while
expropriations for environmental reasons may be legitimate, they do not alter the state’s obligation to pay full
compensation. The tribunal emphasized that environmental motivations, however commendable, do not affect the legal
nature of the expropriation nor the amount of compensation due under international law.
In contrast, in the 2018 Aven v. Costa Rica case, the tribunal adopted a more nuanced approach. While acknowledging
that investors’ rights under DR-CAFTA remained applicable, the tribunal recognized that these rights were
subordinated—though not absolutely—to the host state’s environmental policies, provided the state acted in
accordance with international law and principles such as good faith. The decision reflected a deeper integration of
environmental protection within the legal reasoning, demonstrating increased deference to state regulatory powers
when aligned with treaty objectives.
Importantly, the outcomes of the two cases also differed. While the Santa Elena tribunal awarded $16 million in
compensation (less than claimed), the Aven tribunal dismissed the investor’s claim entirely, showing that factual
circumstances and context remain decisive in arbitration outcomes. It is therefore inappropriate to assume that an older
case like Santa Elena would have necessarily reached a different result under the standards of 2018.
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Since ancient times, trade has been fundamental to the economic prosperity of societies. In modern
international law, trade relations were primarily governed by bilateral agreements between states
until the end of World War II in 1945.
The economic crisis of the 1930s and the destruction caused by the war revealed the limitations of
protectionist policies. As a result, emerged a strong global consensus on the need to shift towards a
multilateral trade system, despite opposition from socialist countries.
This shift began with the 1941 Atlantic Charter, in which the Allied powers pledged to ensure equal
access to global trade and raw materials. It was followed by the 1948 Havana Charter, which laid the
foundation for the proposed International Trade Organization (ITO), envisioned as the key
multilateral institution to regulate world trade.
However, the ITO never came into existence because the U.S. Congress refused to ratify the Havana
Charter, reflecting a return to protectionist sentiment. As a result, the General Agreement on Tariffs
and Trade (GATT), which had been adopted in 1947 by ECOSOC as a provisional framework, remained
in force. For nearly fifty years, GATT functioned as the main platform for multilateral trade
negotiations (known as “rounds”), promoting the liberalization of trade in goods.
The end of the Cold War brought a renewed commitment to multilateralism. In 1994, the World
Trade Organization (WTO) was established. The WTO institutionalized the GATT framework, and the
agreements reached during its negotiation rounds. Furthermore, it expanded the scope of
international trade law to include not just goods (GATT), but also services (GATS) and intellectual
property rights (TRIPS).
An important aspect of the institutionalization of the World Trade Organization (WTO) is its Dispute
Settlement Understanding (DSU), which introduced a binding dispute settlement mechanism. This
system, which includes an appellate procedure, represents a major development in the enforcement
of international economic law.
When a trade dispute arises between WTO Members and cannot be resolved through consultation,
the matter is brought before the Dispute Settlement Body (DSB), which consists of all WTO member
states. The DSB establishes an ad hoc panel to hear the case and issue a report. If either party
disagrees with the panel’s findings, it can appeal the decision to the Appellate Body, whose ruling,
once adopted, becomes final and binding.
As of the signing of the WTO Agreements in 1994, 128 countries had joined the GATT. Today, the
WTO counts 164 members, including major players like China and Russia.
The WTO wants to promote the rule of law in international trade, especially regarding fair,
administrative procedures and access to justice. The organization is built on the principle of nondiscrimination:
1) National Treatment: WTO members must treat foreign good no less favorably than domestic
equivalents.
2.
Most-Favored Nation (MFN): As stated in Article I of the GATT, any advantage given to
one country must be extended unconditionally to all others.
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These trade rules are increasingly linked to public policy objectives, such as sustainable
development, improved living standards, employment, and equal pay. The GATT permits exceptions
to trade obligations in cases where restrictions are necessary to protect human, animal, or plant life
or health (Article XX(b)), or to uphold public order and morals.
Despite these advances, the multilateral trading system faces serious challenges. Since 2016, the
United States has blocked the appointment of new judges to the Appellate Body, effectively
paralyzing the appellate process. This situation illustrates a broader crisis of multilateralism,
threatening the effectiveness and credibility of the WTO dispute settlement system.
5.The law of the sea is a branch of public international law that governs how states use and manage
ocean spaces. It should not be confused with maritime law, which deals with private legal matters
like shipping, contracts, and liability, usually under domestic legal systems.
From the late 16th century until the mid-20th century, customary law recognized two main
principles:
- Coastal states had sovereignty over a narrow territorial sea, traditionally 3 nautical miles.
- Beyond that, the high seas were open to all under the principle of freedom of navigation and
trade.
This minimalist system remained unchanged for centuries. However, 20th-century developments
demanded new legal rules. The process unfolded through several key stages:
First the 1930 Hague Codification Conference – limited progress. Then in 1958 First UN Conference
on the Law of the Sea (UNCLOS I) – adopted four key conventions:
o Territorial Sea and Contiguous Zone
o High Seas
o Continental Shelf
o Fishing and Conservation of Living Resources
These introduced zonal regulation—different rules depending on distance from shore and
activity type.
Then in 1960 Second UN Conference (UNCLOS II) – failed to reach consensus. Between 1973–1982
Third UN Conference (UNCLOS III) – resulted in the 1982 UN Convention on the Law of the Sea
(UNCLOS). Secondarily UNCLOS (Entered into force 1994) was ratified by 170 parties (169 states +
EU), contains 320 Articles, 9 Annexes, and a Final Act. Has a comprehensive framework regulating
maritime zones, navigation rights, marine resources, and environmental obligations. UNCLOS
defines seven main maritime zones:
- Internal Waters**: Full sovereignty, same as land territory. Foreign vessels need permission
to enter, except in emergencies.
- Territorial Sea (up to 12 nm)**: Coastal state has full sovereignty over water, airspace,
seabed, and subsoil. Subject to the right of innocent passage for foreign vessels. Passage
must be continuous, not threatening, and non-prejudicial. Activities like spying, fishing, or
weapons exercises make it non-innocent. Controversy: some states require prior notification
for warships; others (e.g., US) reject this.
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-
-
-
Contiguous Zone (up to 24 nm): Not full sovereignty, but coastal states can enforce laws
related to: Customs, Taxation, Immigration and Sanitation.
Exclusive Economic Zone (EEZ – up to 200 nm): Coastal states have sovereign rights over:
Natural resource exploration and exploitation (fisheries, oil, wind energy) and must respect
rights of other states (e.g., navigation, overflight, laying cables).
Continental Shelf: Seabed and subsoil only (not water column). Default: up to 200 nm,
possibly more if natural extension proven. Coastal states have sovereign rights to seabed
resources; rights exist automatically (ipso facto, ab initio).
High Seas: Open to all states (navigation, fishing, scientific research). Must cooperate on
resource conservation.
The Area: Seabed beyond national jurisdiction. Declared “common heritage of humankind”
(Article 136). Managed by the **International Seabed Authority (ISA)** to ensure equitable
benefit-sharing and regulation.
For the resolution of disputes, UNCLOS provides binding mechanisms: ITLOS, International Court of
Justice (ICJ), and arbitration.
For Maritime delimitation disputes (where zones overlap): it uses equidistance and equity principles
to reach fair solutions. Courts consider geography, socio-economic impact, and environmental
factors.
UNCLOS Part XII sets binding obligations to prevent, reduce, and control marine pollution (from land,
vessels, seabed, atmosphere); conduct Environmental Impact Assessments (EIAs) for harmful
activities; protect ecosystems and biodiversity and finally cooperate internationally and ensure
accountability.
2023 BBNJ Agreement (Biodiversity Beyond National Jurisdiction): addresses legal gaps in UNCLOS
for the high seas and international seabed. Introduces rules on:
- Marine genetic resources
- Marine protected areas
- EIAs
- Capacity-building for developing states
2024 ITLOS Advisory Opinion on Climate Change: declared GHG emissions absorbed by oceans as
marine pollution under UNCLOS. Clarified that states’ marine protection duties must align with
international climate commitments (e.g., Paris Agreement). Endorsed the precautionary principle—
states may adopt stricter measures.
Ongoing ICJ Advisory Opinion (Requested in 2023, Expected late 2025) will address: States’ legal
obligations to protect the climate system and environment from GHG emissions. Legal consequences
for states responsible for climate harm, especially affecting vulnerable nations and future
generations. More than 100 delegations participated in hearings.
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6. Human rights, though a recent area of international law, have long been central to national legal
systems through instruments like the Magna Charta, the French and American declarations, and
constitutional protections against slavery and discrimination.
Historically, international law refrained from interfering in how states treated their own nationals,
adhering to the principle of sovereignty and non-intervention. This was especially emphasized
during the Cold War by states like the USSR and China in response to Western critiques.
After the Cold War, states across ideological lines began to engage with human rights treaties. This
broad participation, supported by consistent legal belief (opinio juris), has elevated core human
rights to the level of customary international law.
Violations of human rights norms, such as torture, do not negate their legal status so long as states
maintain the belief that such norms remain binding. The endurance of these norms relies not on
compliance alone, but on a shared legal conviction of their legitimacy.
International human rights law represents a shift from a system based on state interests to one
centered on individual rights. Individuals are now rights-holders under international law by virtue of
their humanity, and states are bound to protect these rights even toward non-citizens.
This approach is rooted in the UN Charter, which commits member states to promoting respect for
human rights. Though the Charter does not list specific rights, it laid the foundation for institutions
like the UN Commission on Human Rights and its successor, the Human Rights Council.
The 1948 Universal Declaration of Human Rights was the first global statement of fundamental
rights, encompassing civil, political, economic, social, and cultural rights. Though non-binding, it
influenced subsequent binding treaties.
In 1966, the ICCPR and the ICESCR were adopted to give binding force to the UDHR. These Covenants
entered into force in 1976 and with the Declaration formed the International Bill of Human Rights.
They created treaty bodies that monitor compliance and accept individual complaints under
protocols.
Regionally, Europe led the way with the European Convention on Human Rights and the
establishment of the European Court of Human Rights. America followed with the American
Convention and the Inter-American Court, accessed through a commission. In Africa, the African
Charter and Court emerged, combining individual and collective rights, with limited access based on
state declarations.
The European Union added the Charter of Fundamental Rights, which became legally binding in
2009. It applies specifically to EU institutions and member states when implementing EU law.
Outside these regions, protections are weaker. The Arab Charter and ASEAN Declaration recognize
human rights principles but lack strong enforcement or complaint mechanisms.
Human rights treaties create obligations between individual states and toward the international
community in the case of core norms like the prohibition of genocide or torture.
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Although many rights in international treaties resemble those already found in national
constitutions, the real strength of international human rights law lies in the external mechanisms it
establishes to enforce those rights, especially when domestic systems fall short.
This is particularly important in an era of growing legal nationalism, where domestic courts and
governments may resist international oversight. Without meaningful engagement between national
and international systems, the dialogue risks becoming ineffective.
7. Migration is one of the most complex challenges facing the international community, marked by
intense movements through regions. These flows generate significant political and social tension,
often sidelining the legal aspects of migration.
The term “migration law” spans several areas, including human rights, refugee law, the law of the
sea, labor law, and increasingly, environmental law in response to climate-induced displacement.
Migration policy remains a core aspect of state sovereignty, allowing wide discretion over who may
enter and remain. However, this discretion is limited by international legal obligations, especially
human rights law, which applies to all individuals.
Refugees are entitled to specific protections under the 1951 Refugee Convention and its 1967
Protocol, administered by the UNHCR. These instruments define refugees as those fleeing
persecution based on factors such as race, religion, or political opinion, and prohibit their return to
places where they face serious harm (the principle of non-refoulement).
This principle, part of customary international law and possibly jus cogens, forbids returning
individuals to countries where they may face torture or threats to life or freedom, though exceptions
exist for national security concerns or serious crimes.
Refugees also benefit from access to services, education, housing, and employment protections,
though not political rights. States must allow asylum seekers to remain during status determinations
and grant them a legal right to reside if recognized as refugees.
In contrast, economic and irregular migrants are not granted the same legal status, and their
treatment remains largely a matter of domestic regulation.
In maritime contexts, legal duties to assist migrants in distress at sea arise from customary
international law and treaties like UNCLOS, SOLAS, and the SAR Convention. These rules obligate
both public authorities and private vessels to prioritize saving lives.
States are also required to coordinate rescue efforts, share information, and allocate search and
rescue zones, reflecting a shared international responsibility to prevent deaths at sea.
Those displaced by environmental causes are not covered under the Refugee Convention’s
definition. However, there is increasing legal discussion on extending similar protections to
environmentally displaced persons.
The 2018 UN Global Compact for Safe, Orderly and Regular Migration reflects a soft-law approach
to migration governance. While non-binding, it promotes cooperation, protection of rights, and
measures to counter trafficking and promote decent work.
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8. International environmental law is a relatively recent but increasingly significant branch of
international law that began developing in earnest in the late 1960s and 1970s.
Its emergence was driven by growing scientific awareness of environmental degradation caused by
industrialization, pollution, and the unsustainable use of natural resources.
It is still evolving and remains fragmented across various issue-specific treaties, known as
Multilateral Environmental Agreements (MEAs).
These MEAs typically take the form of framework conventions that establish general obligations and
principles. More specific rules are developed later through protocols, guidelines, and decisions by
treaty bodies like Conferences of the Parties (CoPs).
While the field may seem disjointed, it is held together by a core set of principles that are repeatedly
echoed in soft law instruments like the Stockholm Declaration (1972) and the Rio Declaration (1992).
Over time, these principles have influenced binding treaties and customary international law.
Environmental concerns are also increasingly integrated with other legal areas.
Human rights bodies, such as the European Court of Human Rights, have interpreted existing rights
(e.g., the right to private life) in ways that incorporate environmental dimensions.
In the investment context, arbitration tribunals now weigh environmental regulations against
investor protections, especially when disputes arise over regulations that affect foreign assets.
Similarly, under international trade law, environmental measures can justify exceptions to trade rules
if they are non-discriminatory and proportionate.
Judicial decisions have further reinforced the normative strength of environmental principles.
A key example is the Gabcikovo-Nagymaros case, where the International Court of Justice emphasized the need to
interpret older treaties in light of new environmental norms like sustainable development.
9. The principle of jurisdictional immunities has evolved from an absolute protection of sovereign
states to a nuanced and restrictive regime. This transformation reflects changing understandings of
sovereignty, the rise of constitutionalism, and the expansion of international legal obligations.
Rooted in the Westphalian model, traditional state immunity meant that one sovereign could not be
judged by another. This applied broadly to states, their officials, and their property.
As modern legal systems began distinguishing between the state and its officials, separate rules
developed for different categories of actors—especially high-ranking officials.
In the 20th century, particularly after the rise of state-led economies, courts began distinguishing
between sovereign acts (acta jure imperii) and commercial acts (acta jure gestionis). This restrictive
doctrine gained widespread acceptance and was codified in the 2004 UN Convention on
Jurisdictional Immunities (not yet in force).
The restrictive model also differentiates between being sued and the enforcement of judgments.
Even if liability is found, certain state property remains protected from seizure.
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A growing debate concerns whether states can retain immunity in cases involving grave international
crimes (e.g., genocide, war crimes). Some domestic courts, such as Italy’s in the Ferrini case, have
denied immunity for such claims, arguing that jus cogens norms must prevail. However, the ICJ in
2012 rejected this exception, maintaining that no such customary rule exists in international law.
-
Diplomatic immunity (ratione personae) is broad but temporary, covering both official and
private acts during service.
Functional immunity (ratione materiae) protects officials for acts done in an official capacity,
regardless of when proceedings are initiated, and continues after they leave office.
In international criminal law, functional immunity no longer protects individuals accused of
international crimes. This has been affirmed by international courts and reflects the post-Nuremberg
consensus that no one is above the law for crimes like genocide or torture.
Cases like Enrica Lexie show that functional immunity remains important in inter-state disputes, but
also highlight the legal and moral tensions when immunity intersects with demands for
accountability.
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