Sources of Criminal Law

Criminal law defines crimes; sets the procedures for arrests, searches and seizures, and interrogations; establishes the rules for trials; and specifies the punishments for offenders. Where does criminal law come from?

Common law

Common law, which is known as judge‐made law, came into existence in England during the twelfth century. Judges created common law by ruling that certain actions were subject to punishment and defined offenses such as murder, rape, arson, and burglary as crimes against the state. Over time, British judges' law decisions produced a body of unwritten laws and customs. This law formed the basis of the legal system in the American colonies.

One of the main parts of common law is the law of precedent. Once a court makes a decision, it is binding on other courts in later cases presenting the same legal problem. The principle of stare decisis relates to the law of precedent. It literally means to “let the decision or precedent stand.” This principle guides courts in making decisions in similar cases and ensures fairness in the judicial process.


Article VI of the U.S. Constitution asserts that “This Constitution … shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.” If any other types of law conflict with the Constitution, the U.S. Supreme Court can strike them down as unconstitutional. States make their own constitutions and all local laws are subordinate to them.

Statutes and ordinances

Laws passed by Congress and by state legislatures make up most of criminal law. City councils also pass ordinances that compose part of criminal law. Each state has a statutory criminal code, as does the federal government. Laws defining crimes such as homicide, rape, robbery, burglary, and larceny are generally statutory. Some overlap exists between state and federal statutes. For example, some federal drug laws supplement state laws. Such laws are intended to provide added crime control in areas where local law enforcement has been ineffective.

Administrative rules with criminal penalties

U.S. governmental agencies and commissions make rules that are semilegislative or semijudicial in character. The Federal Trade Commission (FTC), Internal Revenue Service (IRS), and Environmental Protection Agency (EPA) are examples of administrative agencies that make such rules. These agencies formulate rules, investigate violations, and impose sanctions. They enforce rules relating to a variety of crimes, including securities fraud, income tax evasion, selling contaminated food, and dumping toxic waste.

Appellate court decisions

Legal opinions having the status of law as stated by the appellate courts (for example, the U.S. Supreme Court) become case law. Such law results from appellate court interpretations of statutory law or from court decisions where rules have not yet been codified in statutes.