Why Are There Wars?
LAY
War is an extremely costly way
for states to settle their disputes. Given the
human and material costs of military conflict, why do states sometimes wage war rather
than resolve their disputes through negotiation?
Aboye: States may go to war over territory that they
consider integral to their nation. In 2020, Indian
and
Chinese soldiers clashed
Control
in
Ladakh,
a
disputed
along
the
territory
Line
that
of
lies
between the two countries. The conflict resulted in
20 Indian casualties. Could tensions over the region
lead to war?
In Aug ust 1914, the major countries of Europe embarked
on a war the likes of which the world had never before
seen. Convinced that the war would
European
a fight
have
into
millions
injured,
displaced
from
their
homes and countries, impoverished, and diseased.
be over by Christmas,
leaders sent a generation of young men
left untold
War has economic and material costs as well. Since
2001,
the
United
States
has
spent
over
$2
trillion
on
that would last four years and claim more than
military operations in Iraq, Afghanistan, and Syria.2 Nations
15 milllion lives. The fighting was so intense that in one
" also routinely spend large sums of money to prepare for
battle t he British army lost 20,000 soldiers in a single day,
the possibility of war. In 2020, military expenditures by all
as wave after wave of attacking infantry were cut down
countries amounted
by Ger man
$250 per person.® Wars can also disrupt the international
machine guns. At the time, it was called the
to just under $2 trillion—or about
Great War. Those who could never imagine another such
economy.
horrific event dubbed it the “war to end all wars.” Today,
we know this event as the First World War, or World
ing the Iran-lrag War (1980-88), the Persian Gulf War
War
|,
because
Conflicts
in the
oil-rich
Middle
East,
20 years later the countries of Europe
were
at it once again. Wortd
30-50
million lives.
and
War ll [1939-45) claimed
Nils Petter Gleditsch,
nds in Global Comb
European Journal of Population 21 (2005):
Th ere is no puzzle in the study of international politics morre pressing and important than the guestion of why
wford, “United
states go to war. It is the most tragic and costly phenomenon thatwe observe in social and political life. The costs of
most
war cam be counted on a number of dimensions. The
obvious cost is the loss of human life. By one estimate,
40 million
wars arnong states in the twentieth century led to
of millions more
deaths directly from combat, plus tens
In addi
deaths linked to war-related hardships.'
and d
defense
N
ditional expen:
m and commitments to v
Sily:
in World Milit
tion
publi
-expenditure-2020 (
“Monitoring
ew Dataset of Battle Deaths,”
includ-
contributed to
[1990-91), and the lrag War (2003-10],
Civil War general
spikes in world oil prices. In short, as U.S.
“War is hell.”
William Sherman famously declared,
But if everyone recognizes that war is hell, why do
wars
happen?
The
costs that make
the
enormous
so perplexing.
costs associated
with war,
why
would states sometimes choose this course?
At first glance, the answer might seem straightforward:
g interests
states fight wars because they have conflictin
s
over important issues. Often, for instance, two state
desire the same piece of territory. Nazi Germany wanted
to expand into Central Europe; World War lI started when
the Poles, who did not want to give up their land, fought
back. In 1980, Irag invaded Iran, in part, to seize the latter's southern oil fields, leading to the Iran-lrag War. Alternatively, one state might object to the policies or ideology
of another. World War | grew out of Austria-Hungary's
demand that Serbia end its support for nationalist movements that threatened to tear the multiethnic AustroHungarian
Empire apart. War between the United States
and Afghanistan
broke
out in 2001
because
the
United
States wanted Afghanistan to hand over Osama bin Laden
and
dismantle
terrorist training
camps
on
its territory,
something that the Afghans refused to do. Clearly, part of
the explanation for any war reguires that we identify the
conflicting interests that motivated the combatants.
While such interest-based explanations are correct,
they are also incomplete. By identifying the object or issue
over which a war was fought, they neglect the key guestion
of why states resorted to war in order to resolve their dispute. In each case, the conflicts were disastrously costly to
at least one and, in some cases, all the states involved. In
addition to the millions of dead mentioned earlier, World
War | led to the ouster of three of the leaders who brought
their countries into the war, and it hastened the breakup
of the Austro-Hungarian, Russian, and Ottoman empires.
World War ll brought about the defeat and occupation of
its main instigators, Germany and Japan. The Nazi leader
Adolf Hitler committed suicide, and his Italian ally Benito
Mussolini was hung by his own people. Iran and Irag
fought for eight years only to end their conflict in a stale-
mate, causing 1-2 million casualties and leaving Iraq on
the brink of economic collapse. The Afghan government's
refusal of U.S. demands led to its removal from power
and,
10 years later, to bin Laden's death at the hands of American soldiers. Given these grave conseguences,
it makes
îïïb;î.;o:,îï ‘:lhelher all participants would have
ey could have come to a settlement
94
partici-
req
Explaining war thus
such ai greements.
pants fail to reach
of war
the phenomenon
so pressing also make
Given
the puzzle
costs of war,
d them to avoid Hthe
owe
all
t
d
tha!
g
beforehan
uires us to explain why its
Thinking Analytically about
Why Wars Happen
states are settled without the
to capture
parties resorting to war. Although wars tend
war is
our attention, it is important to remember that
Most disputes between
an exceedingly rare
phenomenon;
most
countries are
3.1
at peace with one another most of the time. Figure
te wars in
shows the number of states involved in intersta
age
each year from 1820 to 2020, expressed as a percent
of the total number of states in existence at the time. As
the figure indicates, war is a recurrent feature of international politics in the sense that it fluctuates in freguency
but never disappears completely. Yet war is the excep-
tion rather than the rule: in most years, the percentage
of states involved in war is guite low. All this peace cannot be explained by an absence of issues to fight over.
Hence, when seeking to explain war, we need to
ask not only “What are these parties fighting over?” but
also “Why are they fighting?”“ n terms of the framework laid out in Chapter 2, answering the first guestion
requires us to understand how states' interests can give
rise to conflicts over things like territory, policies, and
the composition or character of each other's governments. The answer to the second guestion lies in the
strategic interactions that determine whether or how
these conflicts are resolved. As we saw in the previous
chapter, the international system
such
as legislatures,
courts,
lacks institutions—
or international
police
forces—that can resolve conflicts between states through
legal, judicial, or electoral mechanisms. As a result,
interstate
conflicts have to be settled through bargaining. Understanding why wars occur reguires us to
identify the factors that sometimes prevent states from
settling their conflicts through peaceful bargains that
would permit them to avoid the costs of war.
' IneJ theory of war developed in this chapter relies extensively
'n
ames D. Fearon, “Rationalist
nations for War,”
nternational Organization 49, no. Expla
3 (Summer 1995): 379-414.
FIEUNE3.1
es Invo Ived in Interstate War per Year, 1820-2020
at
St
of
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ta
en
rc
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15
T
1840
1860
1880
1900
1920
1940
1960
What Is the Purpose of War?
2000
1980
2020
Figure sources: Meredith Reid
Sarkees and Frank Wayman,
Resort to War: 1816-2007
(Washington, DC: CQ Press,
2010). Updated to 2020 by
A war is an event involving the organized use of military force by at least two parties that reaches a minimum threshold of severity.* Every component of this definition is important. The reguirement that force be organized rules out spontaneous,
disorganized violence, such as large-scale rioting. The reguirement that force be
used by at least two parties distinguishes war from mass killings perpetrated by a
government against some group that does not fight back. The minimum threshold—
scholars often require that a war cause at least 1,000 battle deaths—excludes cases
in which military force is used at low levels, such as brief skirmishes or minor
clashes. If the main adversaries in the conflict are states, then we refer to the
author.
war
An event involving the
organized use of military
force by at least two parties
that reaches a minimum
threshold of severity.
event as an interstate war; if the main parties to the conflict are actors within a
state—such as a government fighting a rebel group—then the event is a civil war.*
This chapter focuses on understanding interstate wars. Chapter 6 covers conflicts
interstate war
involving nonstate actors, including civil wars.
Given that scholars have been trying to understand war for millennia, the num-
civil war
ber of theories and explanations that have been proposed over the years is naturally quite large, and the bargaining model that we lay out in this chapter is only
one approach. At least three other broad schools of thought have been influential
in modern scholarship. While these approaches contribute important insights, they
also have gaps that are filled by the bargaining approach.
The first, described in this book's Introduction as realism, argues that war is
the inevitable result of international anarchy (pp. xxxiv-xxxvi). The absence of a
5. See, for example, J. David sin|er and Melvin Sni-d!. The
(New York: Wiley, 1972).
6. There uul.wnuuthq_hlneknmg
muummfmvâwl
|
A war in which the main
participants are states.
A war in which the mai
participants an'wîthiwfg
the same state, such
|
|
central authority capable of policing interstate relations means that wars can happen
because there is nothing to stop states from using force to get their way.” Moreover,
anarchy creates insecurity and motivates states to compete for power. In this view,.
states fight wars either to increase their own power (for instance, by enlarging their
territory) or to counter the power of others (by destroying adversaries and their
allies). For this reason, realism emphasizes two primary dynamics that can lead to
war. One is a preventive motive: the desire to fight in order to prevent an enemy
from becoming relatively more powerful.* The second is a phenomenon known as
the security dilemma. This dilemma arises when efforts that states make to defend
security dilemma
A dilemma that arises when
efforts that states make to
defend themselves cause
other states to feel less
secure; can lead to arms
races and war because of
the fear of being attacked.
themselves, such as enlarging their militaries, make other states fear that they will
be attacked. If these threatened states arm themselves in response, the result is a
spiral of fear and insecurity that may end in war.”
As we will see, the bargaining model of war shares realism's presumption that
anarchy leads to a world in which states often use or threaten to use military force
to further their interests and that states address conflicts through bargaining rather
than institutions like courts. The bargaining model also anticipates prevention and
the fear of attack as two of several motives that can lead to war. Its main departure
from realism is in recognizing that the use of military power imposes costs on
states, so even if threatening force is useful to get a better deal, states are generally
better off if they do not have to actually use force—creating the puzzle that is at the
heart of this chapter.
A second alternative to the bargaining model emphasizes the role of misper-
ceptions or mistakes. Starting from the observation that the costs of war often far
exceed any potential benefits, scholars in this tradition conclude that wars must
occur because decision makers inaccurately estimate their chances of winning or
the costs that they will have to pay. When European leaders sent their armies to war
in August 1914, most were convinced that the troops would be home by Christmas—a
prediction that turned out to be off by four years. Both sides also expected to win
the war, meaning that at least one side was being overly optimistic. This kind of
argument rests either on research in cognitive psychology—which shows that people are bad at weighing risks and often fall prey to wishful thinking—or on organizational approaches that emphasize how the ideology and interests of political and
military elites can lead to incorrect and overly optimistic assessments of war.ì9
A concern about such theories is that while perceptual pitfalls are universal,
war is guite rare, and these theories have a hard time explaining why wars happen
at some points in time but not others. As we will see, uncertainty about the likely
m
Kenneth N. Waltz, Theory of International Politics (1979; repr., Long Grove, IL: Waveland Press, 2010).
. See, for example, Dale C. Copeland, The Origins of Major War (Ithaca, NY:
Cornell University Press,
2000); and Stephen Van Evera, Causes of War (Ithaca, NY: Cornell University Press, 1999).
9. Robert Jervis, “Cooperation under the Security Dilemma,” World Politics
30, no. 2 (January 1978):
167-214.
10. The classic work applying cognitive psychology to internat
ional relations is Robert Jervis, Perception
and Misperception in International Politics (Princeton, NJ: Princet
on University Press, 1976). For an
argument that military ideologies can lead to incorrec
t and overly optimistic assessmei
see Stephen
Van Evera, “The Cult of the Offensiv
e and the Origins of the First World War”
Internatonal Security 9,
no. | (Summer 1984): 58-107. The effect
of military biases
influence the degree to which civilians control the military:may depend on domestic institutions thar
this argumentis takenup in Chapter 4.
ï
96
Chapter3
WhyAre There Wars?
outcome and costs of war plays an important role in the bargaining model approach
developed here. However, we emphasize not the psychological or organizational
origins of potential mistakes but rather the difficulties of gathering necessary
information in the strategic context of bargaining.
Finally, a long tradition of scholarship argues that wars are fought not because
they serve the interests of states but because they serve the interests of influential
groups within states, such as corporations, arms merchants, and the military." In
this view, the puzzle of war has an easy answer: Wars are fought in spite of their
costs because those costs do not fall on the actors who call the shots. Although this
chapter introduces the bargaining model by treating states as the main actors, we
will see in Chapter 4 that the potential role of internal politics and domestic interests can be incorporated guite easily.
Interests at War: What Do States Fight Over?
At the root of every war lies a conflict over something that states value. The pur-
pose of warfare is not to fight but rather to obtain, through fighting or the threat of
fighting, something the state wants. Hence, we should think about the problem of
war as a problem of bargaining over objects or issues that are of value to more than
one state. Using the framework developed in Chapter 2, we focus on situations in
which states' interests conflict, giving rise to a strategic interaction that involves
bargaining over the distribution of whatever is in dispute. The analysis thus starts
by assuming that there is an object of value—what we will sometimes refer to as a
“good”—and that each state prefers more of the good over less.
‘What kinds of goods do states fight over? Territory has historically been the
most common source of trouble. Indeed, a study of 155 wars over the last three cen-
turies found that over half (83) involved conflicts over territory—more than any
other single issue.”? States come into conflict if more than one wants the same piece
of territory. There are a number of reasons why a piece of territory may be valuable
to more than one state. First, it might contribute to the wealth of the state, particularly if it contains valuable resources such as oil, natural gas, or minerals. For
instance, the lengthy Iran-Irag War stemmed in part from the fact that Irag coveted
Iran's southern oil fields. Territory can also be economically valuable simply because
it would add to the industrial or agricultural resources at the state's disposal.
Territory may also cause conflict between two states because of its military or
strategic value. For example, the Golan Heights, on the border between Israel and
Syria, has a commanding position over northern Israel from which it is possible
to Jaunch devastating attacks on the towns below. Israel seized the Golan Heights
from Syria in the 1967 Six Day War, and this territory has been a source of conflict
between the two states ever since.
Finally, a piece of territory might be valuable for ethnic, cultural, or historical
reasons. The long-standing conflict between Israel and its Arab neighbors stems
11. See citations to this literature in Chapter 4.
12. Kalevi J. Holsti, Peace and War: Armed Conflicts and International Order, 1648-1989. (Cambridge:
Cambridge University Press, 1991).
What Is the Purpose
of War?
97
MMP 31
Territorial Claims in the Kashmir Region
TAJIKISTAN
Area ceded by Pakistan —
to China, claimed by India
CHINA
AFGHANISTAN
R
JAMMU & KASHMIR
Indian-controlled
Line of Control
Area held by China,
claimed by India
Disputed areas
from the latter’s resistance to the creation of a Jewish state on land where many
u
8
h
.
U
lineafter the FirstKeshmir War _ Arabs had lived. In this case, the dispute goes beyond simply the location of a
Map note: The Line of Control,
which originated as a cease-fire
border, as some Arab states have refused to recognize Israel’s right to exist."*
‘;‘.e Ak
‘“"ij‘; 'akistanif’"i’;’?)'
Indian- an;
into
Similarly, the long-running conflict between India and Pakistan over the
Kashmir region is driven by the fact that both have historical and ethnic claims to
administered areas.
the land. When the two countries gained their independence from Britain in 1947,
India pressured Kashmir's Hindu leader to join with India, which is predominantly
Hindu. However, because the people of Kashmir, like the people of Pakistan, are
predominantly Muslim, Pakistan has claimed the territory on the basis of religious
ties. Map 3.1 illustrates the current boundaries of the disputed area, which are
further complicated by China's claims to neighboring portions of Tibet. In territorial disputes, states threaten or use military force to compel concessions and/or to
seize and hold disputed land.
Wars can also arise out of conflicts over states' policies. Such conflicts come
about when one state enacts a policy that benefits it but harms the interests of
another state. The conflict that led to the 2003 Irag War centered on Irag's alleged
pursuit of weapons of mass destruction, which the United States saw as a threat to
its broader interests in the region. Ongoing U.S. conflicts with North Korea and Iran.
have similar sources. The armed conflict between Russia and Ukraine that began
in 2014 revolved around the latter's decision to pursue closer economic ties to the
13. Egypt recognized Israel in 1979, and Jordan did likewise in 1994.
98
Chapter 3
Why Are There Wars?
the interests of ethnic Russians living in
wWest, which, according to Russia, harmed
can also spark international
the country. A state's mistreatment of its own citizens
waged war against Serbia in
conflict. For example, the United States and its allies
1999 for its repressive treatment of civilians in the Kosovo region. Similarly,
the
after the government
United States launched cruise missiles against Syria in 2017
deployed chemical weapons on its own people.
of war, may be a mechanism
When states have policy disputes, war, or the threat
s of bombing by
for compelling policy change. In the case of Kosovo, two month
end its military camthe United States and its allies led the Serbian government to
e an offendpaign against the Kosovars. Alternatively, war may be used to replac
This was the
ing regime with a friendlier one that will pursue different policies.
pliant
United States' goal in Irag and Afghanistan, though its efforts to install more
regimes in those countries ultimately embroiled American forces in civil wars that
]asted much longer than the initial operations to oust the former, hostile regimes
(see Chapter 6).
The possibility of using military force to change regimes suggests a third kind
of conflict between states: conflicts over regime type, or the composition of another
country's government. In its conflict with Ukraine, Russia sought to pressure the
Ukrainian government to adopt reforms that would give Ukraine’s Russian minority
greater autonomy and influence. During the Cold War, the United States saw communist regimes as natural allies of the Soviet Union, and hence it sought to prevent
other countries from establishing such regimes. The United States' desire to protect the pro-American South Vietnamese government from internal and external
States
sometimes
threaten or use
military force to
inf
of foreign government
The Syrian governmen
attacked rebel-held
villages with chemical
weapons
in Augu
(pictured here
that it bel
the
What Is the Purpose of War?
99
source
pro-communist forces motivated the country to involve itself in Vietnam's civil war.
(
reguDuring this period, both the United States and the Soviet Union intervened
h
remove
or to
larly in the affairs of other states to prop up friendly governments
will
unfriendly ones. The role of outside powers in civil wars, such as in Vietnam,
be addressed in Chapter 6.
and/or
As the example of Vietnam suggests, conflicts over territory, policy,
ut
ns abo relative
regime may spring from deeper conflicts that give e rise to concer
War II was a dispute between
power. The specific conflict that started World
|
territory that lay between them. HowGermany and Poland over a small strip of
|
a victory over Poland would fur- i
ever, Britain and France were concerned that
formidable foe in their
ther strengthen and embolden Germany, making it a more
Europe. Hence, thfey hada s-take in
ongoing struggle for influence and territory in
dispute because of its ?otennal to
the outcome of the German-Polish territorial
The Cold War rlvalry.betwt'aen
affect their relative power with respect to Germany.
many local conflicts with
the United States and the Soviet Union similarly imbued
to change the bala.nce. of
global importance because of their perceived potential
2, today's tensxfms
power between the two nations. And, as discussed in Chapter
in the South Chj-na
between the United States and China over the latter's claims
would give China
Sea stem in part from the fact that control over that waterway
strategic advantages in any future conflict.
Bargaining and War
sufConflicting interests are clearly necessary for wars to happen, but they are not
ficient to explain why wars actually do happen. To understand why some conflicts
become wars and others do not, we have to think about the strategic interactions
that states engage in when they seek to settle their disputes. In a well-functioning
domestic political system, disputes over the kinds of issues that lead to war between
states are often settled through institutional mechanisms. Property disputes can
be resolved by courts backed by effective police powers. If one person engages in
actions that harm another, the latter may turn to the legal system to solve the
problem. Policy disagreements and conflicting ideas over who should govern can
be settled by elections. As noted in Chapter 2, however, the international system
lacks reliable legal, judicial, and electoral institutions. For this reason, states must
generally try to settle conflicts with one another through bargaining.**
Bargaining describes interactions in which actors try to resolve disputes over
the allocation of a good. They may bargain over the distribution of a disputed territory to determine whether there is a division acceptable to both sides. Or they
may bargain over each other's policies so that objectionable ones might be modified or eliminated. Although we often think of bargaining as entailing compromise
14. Although some interstate disputes have been adjudicated through institutions like the International
Court of Justice (ICJ), these institutions lack strong enforcement mechanisms to guarantee compliance
with their rulings, and disputants often engage in bargaining after an ICJ ruling to determine whether
and how its terms will be implemented. Hence, these rulings are a part of, rather than a substitute for,
the bargaining process. See, for example, Colter Paulson, “Compliance with Final Judgments of the
International Court of Justice since 1987," American Journal of International Law 98, no. 3 (2004): 434-61.
100
Chapter 3
Why Are There Wars?
)
nces will
or give-and-take, the bargaining process does not always imply that differe
s.
position
ing
be split. Indeed, in many cases, states assume all-or-nothing bargain
October 2001 that the
For example, when President George W. Bush demanded in
9/11 terrorist
Afghan government hand over Al Qaeda leaders responsible for the
s
tion or discussion.
attaclcs, he declared that “these demands are not open to negotia
of military force in an
A crisis occurs when at least one state invokes a threat
At this point, we enter the domain
attem pt to influence the outcome of bargaining.
the consequences of not
of crisis bargaining, a bargaining interaction in which
ng war. In such interac-
reach ing an agreement can involve the use of force, includi
tions,
my demands, or else”—where the
at least one state sends the message “Satisfy
“or else” involves imposing costs on the other side through
military action. The use
diplomacy.
of threats in this manner is often referred to as coercive
I3 some cases, this message takes the form of an explicit ultimatum, Z
crisis bargaining
A/ bargaining interaction
lt
n which at least one actor
hreatens to use force in
the event that its demands
are not met.
such as
Saddam Hussein
Presiclent Bush's March 2003 pronouncement that Iragi leader
cases, the threat is
had 4 8 hours to leave the country or face an invasion. In other
y maneuvers or the
conveyyed implicitly through menacing actions such as militar
military incurmobilization of troops. For instance, Russia prefaced its August 2014
es,
sion irito Ukraine by massing troops on the border and running military exercis
y).
but it did not issue an explicit ultimatum or set of demands (at least not publicl
to wrest
Whether explicit or implicit, the purpose of such actions is clear: they seek
a
coercive diplomacy
The use of threats to
advance specific demands in
a bargaining interaction.
YF ] E AT
3F E
BCE(Fe
costly.
concessions from the other side by making the alternative seem unacceptably
T he costs and likely outcome of a war determine which deals each side will
posconsidler acceptable in crisis bargaining. We can generally assume that the best
to fight.
sible coutcome for a state in a crisis is to get the entire good without having
underIf the other side gives in, the state gets its most preferred settlement of the
though,
lying i ssue and avoids paying the costs associated with war. It is quite likely,
ent,
thata state would also accept something less than its most preferred settlem
given that the alternative of fighting is costly.
.
For example, imagine a conflict over a piece of territory worth $100 million
Assumae a state believes that in the event of a war, it is certain to win the territory; how-
ever, the costs of war, if put in monetary terms, would amount to $30 million. In that
=
case, the expected value of going to war for that state is $100 million — $30 million
at least
$70 million. Hence, the state should be willing to accept any deal that gives it
$70 million worth of the territory. Since a state has the option to wage war if it determines that doingso isin its interests, the state will accept a bargain only if that bargain
gives it at least as much as it can expect to get from war. And for any deal to prevent a
war, it must satisfy all sides in this way: each state must decide that it prefers the deal
over fi ghting a war. Hence, in our simple example, war can be averted only if the other
state iss willing to settle for the remaining $30 million worth of territory or less.
The discussion at the outset of this chapter implies a very simple proposition:
Because war is costly, a settlement that all sides prefer over war generally exists.'®
s bin Laden Now,”
15. Elisa beth Bumiller, “Bush Pledges Attack on Afghanistan Unless It Surrender
New
York Times, September 21, 2001, Al
16. See F earon, “Rationalist Explanations for War.”
‘What Is the Purpose of War?
B Tk (;
101
e