Criminal Law

Sources

Criminal law has evolved over the millennia. The Code of Hammurabi is the earliest-known example of an orderly arrangement of a body of laws, pronounced [Page 419]publicly so that citizens might know what behavior was required of them. The code contained a number of rules that are still relevant today, including the principle of “an eye for an eye,” used by some as justification for capital punishment. The Romans also influenced criminal law; the Justinian Code distinguished between two legal categories: public and private law. Public law governs the relationship between a citizen and government. Private law refers to the relationship between a citizen and another citizen. Natural law is also sometimes cited as a source of criminal law. For example, laws prohibiting certain sexual relations (e.g., incest) find their genesis in the belief that such acts contravene the laws of nature.

English common law, however, has had the greatest impact on U.S. criminal law. As distinguished from laws created legislatively, the common law is those principles and rules of behavior that derive their authority from usage, particularly the unwritten law made by English courts, which first accepted certain ancient customs as legally binding. These legalized customs became known as precedents, which themselves became the basis for many of the rules that inform the criminal law today. Although precedents change on occasion, they are the basis for deciding criminal law cases. Such use of precedent is often referred to as stare decisis.

The U.S. Constitution is another source of criminal law because it delegates certain powers to the federal government, and reserves other powers to state governments. Through Congress the federal government has the power to regulate certain areas of public life (e.g., interstate commerce). When Congress passed the Mann Act, for example, it legislated that the transportation of women across state lines for immoral purposes was a criminal act. Regulation of other areas of public life, however, are delegated to the states through the Tenth Amendment; in these areas individual states decide what is lawful within their borders. This amendment has had an interesting effect on criminal law: An act that is illegal in one state may be legal in another. For example, many years ago one had to be twenty-one years of age to purchase beer in Vermont; in neighboring New York it was legal to purchase beer at eighteen.

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