Overview:
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.
Defenses
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]
