criminal law (2024)


Criminal law, as distinguished fromcivil law, is a system of laws concerned with crimes and the punishment of individuals who commit crimes. Thus, where in acivil casetwo parties dispute their rights, a criminal prosecution involves the government deciding whether to punish an individual for either anactor anomission.

A “crime” is anyactoromissionin violation of alaw prohibiting said action or omission.

Criminal Codes

Each state decides what conduct to designate a crime. As such,each state has its own criminal code.Congresshas also chosen to punish certain conduct, codifying federal criminal law inTitle 18 of the U.S. Code. Criminal laws vary significantly among the states and thefederalgovernment. While some statutes resemble thecommon lawcriminal code, others, like theNew York Penal Law, closely mimic theModel Penal Code(MPC).

Codification of Criminal Procedure

Congress codified the federal criminal law andcriminal procedureinTitle 18 of the U.S. Codewith§§ 1 to 2725dealing with crimes. Title 18 designates various conduct as federal crimes, such asarson, use ofchemical weapons,counterfeit and forgery,embezzlement,espionage,genocide, andkidnapping. These statutes usually prescribe a maximum sentence appropriate for a convicted individual. For additional Federal Regulations, consult28 C.F.R.

The federal government has also codified the specific procedures which must take place during a criminal proceeding in theFederal Rules of Criminal Procedure.

Elements of a Crime

An individual commits a crime if they act in a way that fulfills every element of an offense. The statute establishing the offense also establishes the elements of the offense. In general, every crime involves three elements: first, the act or conduct (actus reus); second, the individual’s mental state at the time of the act (mens rea); and third, the causation between the act and the effect (typically either proximate causation or but-for causation). In a criminal prosecution, the government has theburden of proofto establish every element of a crime beyond areasonable doubt.

According to the Supreme Court inElonis v. United States, 575 U.S. (2015), when a statute does not prescribe a specific mental state, a court will infer the “mens rea which is necessary to separate wrongful from innocent conduct.”

Types of Crimes

Crimes can be generally separated into four categories:felonies,misdemeanors,inchoate offenses, andstrict liabilityoffenses.

Each state, and the federal government, decides what sort of conduct to criminalize. Atcommon law, there were nine major felonies (Murder,Robbery,Manslaughter,Rape,Sodomy,Larceny,Arson,Mayhem, andBurglary) and various misdemeanors (i.e.assault,battery,false imprisonment,perjury, and intimidation of jurors).

The U.S. Code is far more extensive than the common law. Nonetheless, Congress has limited power to make criminal laws. As this power is generally reserved to the states, state criminal codes, such as theNew York Penal Law, are far more complicated than the U.S. Code. The N.Y. Penal Law prescribes nine levels of felonies, ranging fromresidential mortgage fraud in the fourth degreetoterrorism.

Sentencing Guidelines

The federal government and state governments have created various sentencing guidelines. Federal courts use theFederal Sentencing Guidelines,while state courts will look at state-specific sentencing guidelines.

Liability forAccomplices

When multiple parties are involved, the traditional first step is to classify the participants according to the following categories:

  • Principal in the first degree– those who actually commit a crime (i.e., the perpetrator).
    • Perpetrators are not accomplices, and this section does not pertain to them.
  • Principal in the second degree– those who aided, counseled, commanded, or encouraged the perpetrator in the actual commission of a crime.
    • An abettor is considered an accomplice.
  • Accessory before the fact– those who aided, counseled, commanded, or encouraged the perpetrator to commit the crime, without actually being present at the moment of perpetration.
    • An accessory (before the fact) is considered an accomplice.
  • Accessory after the fact– those who aid an individual, knowing the individual to be a criminal, in an effort to hinder the individual’s detection, arrest, trial, or punishment.
    • Accessories (after the fact) are guilty of a separate crime, so this section does not pertain to them.

To convict an accomplice, theprosecutorneeds to establish the requisiteactus reusandmens rea. That is, the prosecutor must prove that the accomplice acted in support of the perpetrator and had the requisite mental state while doing so. It is important to note that somejurisdictionsallow accomplices to be prosecuted independently of the principal perpetrator. Thus, an accomplice could be found guilty of a more severe offense than the principal. In certain jurisdictions, an accomplice may beconvictedwhile the alleged perpetrator isacquitted.

Ex Post Facto

Anex post facto lawretroactively punishes actions. The Constitution explicitly forbids this practices inArticle 1, Sections 9 and 10.

Punishing For Status

A law cannot punish a person simply for their status. As the Supreme Court explained inRobinson v. California, 370 U.S. 660 (1962), anystatutethat criminalizes the status of a person inflicts acruel and unusual punishmentin violation of theEighth AmendmentandFourteenth Amendment.

  • For example, a state could not punish an individual for “being homeless,” which would be a status offense, but could punish a homeless individual for trespassing or loitering, which involves some conduct.


There are several defenses available to a defendant in a criminal prosecution. The following list illustrates some common defenses individuals rely on:

  • Failure of Proof – an individual’s simplest defense in a criminal prosecution is to claim that the prosecution has not or cannot prove an element of the offense.
  • Mistakes – in certain circ*mstances, an individual’s mistake can be used as a defense.
    • Mistake of Law– a mistake regarding the legal status or effect of some situation.
    • Mistake of Fact– a mistake regarding the facts of some situation.
  • Justifications – these arecomplete defenses
    • Self-Defense: the use of force to protect oneself from an attempted injury by another.
    • Defense of property: a person may use force to protect theirpropertyfrom a felony occurring within.
    • Defense of Others: the right of a person to protect a third party withreasonableforce against an assailant who seeks to inflict force upon the third party.
    • Necessity: sometimes referred to as the “choice of evils,” the necessity defense allows an individual to engage in otherwise unlawful conduct if by doing so the individual avoids a greater harm.
  • Excuses – these arepartial defenses
    • Duress: an individual may plead duress if another individual forced them to engage in the illegal conduct by force or threat of force.
    • Intoxication: an individual who wasinvoluntarily intoxicatedcan plead intoxication as a defense to every crime.
      • An individual who wasvoluntarily intoxicatedcan plead intoxication as a defense only to crimes that require a specific mental state.
    • Insanity: an insane individual cannot form the requisite mental state, and thus cannot be found guilty.

Further Reading:

For more on criminal law, see thisFlorida State University Law Review article, thisHarvard Law Review article, and thisBoston College International and Comparative Law Review article.

[Last updated in August of 2022 by the Wex Definitions Team]

criminal law (2024)


How to write a criminal law exam answer? ›

The essay questions test your ability to apply the law to the facts. After stating the issue, provide a succinct statement of the relevant legal principles, followed by a detailed analysis of how these legal principles apply to the facts, and a conclusion.

How to do well on criminal law exam? ›

If you complete all of the questions slowly and methodically when you practice, you will learn the legal rules better and you will also internalize the best way to approach questions on your exam. You will not fall for tricks! Closer to your final exam, work on speed.

How to answer legal questions? ›

  1. Brief statement of the legal question. • Your reader wants to know immediately what issue you are seeking to resolve. ...
  2. Succinctly state the legal authority applicable to resolution of the legal issue. • ...
  3. Apply the stated rule to new hypothetical facts. • ...
  4. State your conclusion briefly in 1-2 sentences. •

Why is criminal law so important? ›

The purpose of criminal law is to protect society from harm from criminal behavior. Criminal law does this by deterring people from committing crimes, by punishing those who do commit crimes, and by rehabilitating those who have been convicted of crimes.

Is criminal law exam hard? ›

It also includes 5 one-hour essays and a 90-minute Performance Test, covering other topics in the law, such as Trusts and Wills, and skills, such as writing and argumentation. The California bar exam is considered one of the toughest ones in the country because it has a high minimum passing score requirement.

How to get better at writing law school exams? ›

  1. What to expect from your law school final exams. ...
  2. Understand your professor preferences. ...
  3. Read the facts carefully. ...
  4. Answer the question that is being asked. ...
  5. Organize your thoughts. ...
  6. Complete your analysis and organization before you start writing. ...
  7. Use the IRAC format for each issue raised.

How to answer a criminal law fact pattern? ›

You should always read the question or prompt at the end of fact pattern, but in general your job is to: (1) identify all of the potential legal issues in the fact pattern; (2) identify and state the relevant legal rule(s); and (3) apply those rules to the facts presented to resolve the legal issues.

How to write a legal answer? ›

When drafting an answer, one must: (1) follow the local, state, and federal court rules; (2) research the legal claims in the adversary's complaint; (3) respond to the adversary's factual allegations; and (4) assert affirmative defenses, counterclaims, cross-claims, or third-party claims, if applicable.

Should you answer questions without a lawyer? ›

Many people mistakenly believe they do not need a criminal defense lawyer while answering questions from police detectives. You should have a lawyer present during police questioning, even if you are innocent.

What is an example of criminal law? ›

Examples of criminal law include cases of burglary, assault, battery and cases of murder.

What are the main points of criminal law? ›

Principles of criminal law

The traditional approach to criminal law has been that a crime is an act that is morally wrong. The purpose of criminal sanctions was to make the offender give retribution for harm done and expiate his moral guilt; punishment was to be meted out in proportion to the guilt of the accused.

What are some punishments for criminal law? ›

Types of sentences include probation, fines, short-term incarceration, suspended sentences, which only take effect if the convict fails to meet certain conditions, payment of restitution to the victim, community service, or drug and alcohol rehabilitation for minor crimes.

How do you write an answer law? ›

On a separate page or pages, write a short and plain statement of the answer to the allegations in the complaint. Number the paragraphs. The answer should correspond to each paragraph in the complaint, with paragraph 1 of the answer corresponding to paragraph 1 of the complaint, etc.

How to write law exam questions? ›

To construct an essay exam question, one should (1) select an area covered in a course and jot down issues to test; (2) think of a fact situation that encompasses the chosen issues and will require the students to apply the law to those facts; (3) draft the fact situation and the call of the question; (4) write a model ...

How to use the alac method? ›

It breaks the method down into five steps: Answer, Legal Basis, Analysis/Application, and Conclusion. For the Answer step, examinees should briefly answer yes or no to the question. In Legal Basis, they provide the relevant laws to support their answer. Analysis/Application requires applying the facts to those laws.


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