Actus Reus
A guilty (prohibited) act. The commission of a prohibited act is one of the two essential elements required for criminal liability, the other element being the intent to commit a crime
Administrative Law
The body of law created by administrative agencies (in the form of rules, regulations, orders, and decisions) in order to carry out their duties and responsibilities.
Attempt
The act of taking substantial steps toward committing a crime while having the ability and the intent to commit the crime, even if the crime never takes place.
Attendant Circumstances
The facts surrounding a criminal event. With some crimes, these facts must be proved to convict the defendant of the underlying crime. With other crimes, proving these facts can increase the penalty associated with the underlying crime.
Bill of Rights
The first ten amendments to the U.S. Constitution.
Case Law
The rules of law announced in court decisions. Case law includes the aggregate of reported cases that interpret judicial precedents, statutes, regulations, and constitutional provisions.
Constitutional Law
Law based on the U.S. Constitution and the constitutions of the various states.
Corpus Delicti
The body of circumstances that must exist for a criminal act to have occurred.
Due Process Clause
The provisions of the Fifth and Fourteenth Amendments to the Constitution that guarantee that no person shall be deprived of life, liberty, or property without due process of law. Similar clauses are found in most state constitutions.
Duress
Unlawful pressure brought to bear on a person, causing the person to perform an act that he or she would not otherwise perform.
Duty to Retreat
The requirement that a person claiming self-defense prove that she or he first took reasonable steps to avoid the conflict that resulted in the use of deadly force. Generally, the duty to retreat (1) applies only in public spaces and (2) does not apply when the force used in selfdefense was nondeadly.
Entrapment
A defense in which the defendant claims that he or she was induced by a public official�usually an undercover agent or police officer�to commit a crime that he or she would otherwise not have committed.
Hate Crime Law
A statute that provides for greater sanctions against those who commit crimes motivated by bias against an individual or a group based on race, ethnicity, religion, gender, sexual orientation, disability, or age.
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.
Infancy
A condition that, under early American law, excused young wrongdoers of criminal behavior because presumably they could not understand the consequences of their actions.
Insanity
A defense for criminal liability that asserts a lack of criminal responsibility. According to the law, a person cannot have the requisite state of mind to commit a crime if she or he did not know at the time of the act that it was wrong, or did not know the nature and quality of the act.
Intoxication
A defense for criminal liability in which the defendant claims that the taking of intoxicants rendered him or her unable to form the requisite intent to commit a criminal act.
Irresistible-Impulse Test
A test for the insanity defense under which a defendant who knew his or her action was wrong may still be found insane if he or she was nonetheless unable, as a result of a mental deficiency, to control the urge to complete it.
Mens Rea
(pronounced mehns ray-uh). Mental state, or intent. A wrongful mental state is as necessary as a wrongful act to establish criminal liability.
M'Naghten Rule
A common law test of criminal responsibility derived from M'Naghten's Case in 1843 that relies on the defendant's inability to distinguish right from wrong.
Model Penal Code
A statutory text created by the American Law Institute that sets forth general principles of criminal responsibility and defines specific offenses. States have adopted many aspects of the Model Penal Code, which is not itself a law, into their criminal codes.
Necessity
A defense against criminal liability in which the defendant asserts that circumstances required her or him to commit an illegal act.
Negligence
A failure to exercise the standard of care that a reasonable person would exercise in similar circumstances.
Precedent
A court decision that furnishes an example of authority for deciding subsequent cases involving similar facts.
Procedural Criminal Law
Rules that define the manner in which the rights and duties of individuals may be enforced.
Procedural Due Process
A provision in the Constitution that states that the law must be carried out in a fair and orderly manner.
Recklessness
The state of being aware that a risk does or will exist and nevertheless acting in a way that consciously disregards this risk.
Self-Defense
The legally recognized privilege to protect one's self or property from injury by another. The privilege of self-defense covers only acts that are reasonably necessary to protect one's self or property.
Statutory Law
The body of law enacted by legislative bodies.
Strict Liability Crimes
Certain crimes, such as traffic violations, in which the defendant is guilty regardless of her or his state of mind at the time of the act.
Substantial-Capacity Test (ALI/MPC Test)
From the Model Penal Code, a test that states that a person is not responsible for criminal behavior if when committing the act "as a result of mental disease or defect he [or she] lacks substantial capacity either to appreciate the wrongfulness of his [or her] conduct or to conform his [or her] conduct to the requirements of the law.
Substantive Criminal Law
Law that defines the rights and duties of individuals with respect to each other.
Substantive Due Process
The constitutional requirement that laws used in accusing and convicting persons of crimes must be fair.