
In deciding whether a statute is sufficiently certain and plain, the court must evaluate it from the standpoint of a person of ordinary intelligence who might be subject to its terms. If the language of a statute does not plainly show what the legislature intended to prohibit and punish, the statute may be declared void for vagueness. The elements of a criminal law must be stated explicitly, and the statute must embody some reasonably discoverable standards of guilt. A citizen and the courts must have a clear understanding of a criminal law's requirements and prohibitions. Laws passed by Congress or a state must define crimes with certainty.

Municipalities may make designated behavior illegal insofar as the power to do so has been delegated to them by the state legislature. When classifying conduct as criminal, state legislatures must ensure that the classification bears some reasonable relation to the welfare and safety of society. State legislatures have the exclusive and inherent power to pass a law prohibiting and punishing any act, provided that the law does not contravene the provisions of the U.S. Congress has wide discretion in classifying crimes as felonies or misdemeanors, and it may revise the classification of crimes. Congress has the power to define and punish crimes whenever it is necessary and proper to do so, in order to accomplish and safeguard the goals of government and of society in general. The power to make certain conduct illegal is granted to Congress by virtue of the Necessary and Proper Clause of the Constitution (art. Lesser offenses, such as traffic and parking infractions, are often called violations and are considered a part of criminal law. A misdemeanor is misconduct for which the law prescribes punishment of no more than one year in prison. Crimes that do not amount to felonies are misdemeanors or violations. Most state criminal laws subdivide felonies into different classes with varying degrees of punishment. A felony involves serious misconduct that is punishable by death or by imprisonment for more than one year. The manner in which government enforces this substantive law-through the gathering of evidence and prosecution-is generally considered a procedural matter.Ĭrimes are usually categorized as felonies or misdemeanors based on their nature and the maximum punishment that can be imposed. For example, the law prohibiting murder is a substantive criminal law.

In contrast, Criminal Procedure describes the process through which the criminal laws are enforced.

Substantive criminal laws define crimes and may establish punishments. The term criminal law generally refers to substantive criminal laws. A body of rules and statutes that defines conduct prohibited by the government because it threatens and harms public safety and welfare and that establishes punishment to be imposed for the commission of such acts.
