INTRODUCTION TO CRIMINAL
JUSTICE
Criminal Law in the U.S.
 Criminal law in the U. S. is codified, or written
down, and accessible to all.
 Criminal law is contained in several sources:
---U. S. and state constitutions
---Statute (laws) passed by Congress and state
legislatures; ordinances
---Regulations created by governmental agencies
---Case law (court decisions)
Constitutional Law
 Contained in U. S. constitution and
constitutions of the states
 U. S. Constitution is supreme law of the land
 Each state constitution is the supreme law in
that state
 Conflict between federal and state law,
federal law prevails
Statutory Law
 Congress - Federal laws - applies to all states
 State legislatures - State laws – within the
state’s borders
 Local authorities - ordinances – apply only to
the jurisdictions where it was enacted
Administrative Law
 The rules, orders, decisions of regulatory
agencies.
 Department of Transportation and driving
privileges.
 Food and Drug Administration
Case Law
 The rules of law announced in court decisions
 The whole body of laws and decisions that
have gone before---precedent
 Judges interpret constitutional provisions
 Miranda v. Arizona
 Mapp v. Ohio
Purposes of Criminal Law
 Punish and protect (legal function)
 Maintain social order
 Maintain and teach (social function)
 Teach society changing needs of morality
 Teach society’s boundaries and expectations
 Express public morality—values and norms
Law Terminology
Actus reus
 The guilty act
 The actual physical act
 The voluntary commission of a crime took
place
 Someone had to do something
 Thinking about something wrong is not a
physical act
 Must be a prohibited act
Mens rea
 The guilty mind: Elements of purpose,
knowledge, negligence, recklessness
 Purposefully committed a criminal act
 Knows of the illegality of the act
 Criminal negligence is the deviation of what a
reasonable person would have done
 Criminal reckless is “consciously disregarding a
substantial and unjustifiable risk
Mens Rea Example
 For theft, the required mental state is
knowing that the property belongs to another
and the desire to deprive the owner of it
(The two most used words in the Code of
Iowa are knowingly and willingly, followed by
intentionally.)
Criminal Liability
 The criminal act (actus reus) and guilty mind
(mens rea) must be concurrent (occur at the
same time).
 The criminal act must have caused the harm
suffered.
 Proximate cause---”but for” the actions of the
defendant, the harm would not have occurred.
 Liability differences lead to different penalties
Causation
 Criminal law requires that the criminal act
cause the harm suffered
 Historically, the courts have held that a
victim’s death must occur within one year
and a day before the act to be considered a
criminal act
 Michigan Supreme Court allowed a murder charge
to be filed when the victim died four years later
Strict Liability
 For certain crimes criminal law holds the
defendant to be guilty even if intent to
commit the offense is lacking.
 Example - Traffic violations - I need not know
what the speed limit was; or
---that I was not paying any attention and have
no idea how fast I was going; or,
---that my speedometer was off.
Accomplice Liability
 Under certain circumstances I can be found
guilty of a crime even though I did not
actually commit the crime.
 If I aid and abet in the crime but did not pull
the trigger I can still be charged with murder.
 “Dual intent” is required-----To aid person convicted of crime
---Knew such aid likely to lead to crime
Attendant Circumstances
 Adds to the degree of the crime - If an offender
commits sexual abuse and had used a firearm to
get my victim to submit
 The use of a weapon in an assault
 The amount of money stolen
 Present tendencies are to impose harsher
mentalities if the offense is motivated by race,
ethnicity, religion, gender, sexual orientation
(hate crimes)
Harm
 Harm to a person or property
 The degree of the harm done – stole
$5000.00 rather than $500.00
 Hit a person in the back of their head with a
tire iron
--He/she dies vs.
--He/she is knocked unconscious
Inchoate Offenses
 Conduct deemed criminal without actual harm being
done, provided that the harm that would have
occurred is one the law tries to prevent.
 Solicitation to commit a crime
 Attempts
 The conspiracy to commit a crime
 Sale of drugs
 Other crimes
Types of Defenses
 A defense consists of evidence and arguments
offered by the defendant to show why he/she
should not be held liable for a criminal charge
 Our system generally recognizes four broad
categories of defense
 Alibi
 Justifications
 Excuses
 Procedural defenses
Types of Defenses
 Alibi – different from the other defenses as it
is based on the premise that the defendant is
truly innocent
 An alibi is supported by witnesses and
documentation – hotel receipts, eyewitness
identification
Types of Defense
 Justification – claim of moral high ground; a
choice between the “lesser of two evils”
 Example: a firefighter who sets a “control” fire to
create a firebreak to save the town; The setting of
the fire is arson, but the intent was to save the
town.
 Self-defense; defense of others; defense of home
and property, necessity, consent, and resisting
unlawful arrest
Justifiable Use of Force
Self Defense
 You must use only the force necessary to
protect yourself, your dwelling, your
property, or to prevent a crime.
 Deadly force can only be used to protect you
from imminent death or bodily harm.
 You must not have provoked the attack, and
there must be no alternative.
 You must have a reasonable belief that death
or bodily harm will otherwise occur.
Types of Defenses
 Excuses – the person who engaged in the
unlawful behavior was, at the time, not legally
responsible for his/her actions
 Recognized excuses include:






Duress
- InvoluntaryIntoxication
Age
- Unconsciousness
Mistake
- Provocation
Insanity
-Diminished capacity
Mental incompetence
Necessity
Duress
 The wrongful threat of one person induces
another person to perform an act that she or
he would otherwise not perform.
 Girlfriend helps boyfriend commit a robbery as he
threatens to kill her kids
 The threat must be immediate and
inescapable
Duress
 The threat must be of serious bodily harm or
death
 The defendant must have become involved in
the situation through no fault of his or her
own
Age (infancy) as a Defense
 Under a certain statutory definition you do
not meet the maturity level to make the
decisions necessary to commit a crime.
Mistake
 Ignorance of the law is not a valid excuse
 Mistake of fact – getting into a car that looks
just like yours and putting the key in the
ignition and it works and you drive away is
not a crime.
Insanity Case Law
 Insanity – a legal definition not a medical
definition
 M’Naghten Rule – the inability to distinguish
right and wrong must be the result of some
mental defect or disability
 Irresistible Impulse – Defendant knew it was
wrong but could not stop doing it because of
some irresistible impulse
 Schizophrenia
Insanity Case Law
 Durham Rule--a person is not criminally
responsible for his /her behavior if the
person’s illegal actions were the result of
some mental disease or defect
 Substantial capacity rule—lacks capacity to
appreciate the wrong/or to conform to the
law
“Guilty but mentally ill”
 Jury may decide---defendant mentally ill, but
not insane
 Responsible for his acts
 Defendants spend early years in mental
hospital; to prison at some point
Insanity Defenses
 Temporary Insanity – Insane only at the time
of the criminal act
 Diminished Capacity – Used not to be
declared not guilty, but a lesser sentence;
from Murder 1st degree to Murder 2nd
 Mental Incompetence – Incapable of
understanding the charges against them,
consulting with attorney, or in aiding in their
own defense
Intoxication
 Involuntary intoxication is when a person is
physically forced to ingest a substance.
 Involuntary can also be a reaction to a legal
prescription drug which caused psychotic
episodes as a side effect.
 Voluntary intoxication is becoming
intoxicated on your own. (Claim that there is
no mens rea)
 12 states have eliminated it as a defense.
Necessity (Lesser evils)
 A defense against criminal liability in which the
defendant asserts that the circumstances
required her or him to commit an illegal act.
 Justifiable if harm avoided by your illegal
conduct was greater than that sought to be
prevented in the offense charged
 Violating a restraining order to save your former
spouse from drowning would avoid the greater
evil
Procedural Defenses
 Procedural Defenses – claim the defendant in some
manner was discriminated against in the justice
process, or some important aspect of official
procedure was not properly followed
 entrapment
 Double jeopardy
 police fraud
 selective prosecution
 denial of speedy trial
 Prosecutorial misconduct
Entrapment
 When police deceives defendant into
wrongdoing
 Defendant would not otherwise have
committed crime
 Police cannot “plant the idea” in defendant
 Defense used in some undercover drug cases
Legal Safeguards
 Substantive criminal law---defines specific
acts government will punish
 Procedural criminal law---defines procedures
which must be followed in adjudicating
defendants
Bill of Rights
 First ten amendments to U. S. Constitution,
adopted in 1791
 U. S. Supreme Court has interpreted all of
them
 Serve as a safeguard for accused criminal
defendants
 Procedural safeguards come primarily from
4th, 5th, 6th and 8th amendments
Fourth Amendment
 Protects from unreasonable searches and
seizures
 No warrants for a search or arrest can be
issued without probable cause
 Probable cause is reasonable grounds to
believe the existence of facts warranting
certain actions, such as a search or arrest.
Fifth Amendment
 No one may be deprived of “life, liberty or
property” without due process of law.
 No double jeopardy
 No person can be forced to be a witness
against himself (“taking the fifth”)
Sixth Amendment
 Guarantees a speedy trial, trial by jury, a
public trial
 Right to confront witnesses, right to a lawyer
Eighth Amendment
 Protects against excessive bail and fines
 Protects against cruel and unusual
punishment (Does not include the death
penalty)
Due Process of Law — 14th
Amendment
 Government cannot act arbitrarily or unfairly
 Must stay within the boundaries of reason and
the law
 Procedural due process—law must be carried out
fairly and orderly
 Substantive due process—laws themselves must
be reasonable
 Supreme court has big role in interpreting these
requirements
Hate Crimes
 Offense motivated by hate or bias
 Can involve race, ethnicity, religion, gender,
sexual orientation, disability
 Many states have passed laws enhancing
penalties for other crimes involving hate
 Some of hate laws have been challenged as
violation of constitutional rights
 Say individuals have right to beliefs
 Tends to protect certain victims more than
others