Although the common law provides the basis for defining crimes， federal and state legislatures have enacted statutes that specifically define the elements （ parts） of a crime. For example， common law judges defined rape as sexual intercourse by a man with a woman who was not his wife， against her will and through the use or threat of force. Some modern statutes have modified the elements of thecommon law crime of rape. For example， under some statutes the victim can be either male or female， and a husband can be found guilty of raping his wife. In modern times， both in England and the United States， legislatures have almost completely taken over the task of defining crimes. Judges seldom， if ever， create new definitions of crime， although in England and in many states of the United States they theoretically still have that power.
Until the late18th century， the common law predominated in defining crimes， and there were relatively few—no more than 20 or 30. Today， statutes specify hundreds of crimes in England and in the United States. Matters thatjudges three centuries ago never even thought about—such as carjacking， bribing college athletes， and making false statements in connection with the registration of stocks and bonds—have been classified by legislatures as new statutory crimes.
Although the trend is to add new crimes by statute， to a lesser extent there is a tendency for some crimes of one era to disappear in the next. For example， jurisdictions that once punished witchcraft by death no longer recognize it as a crime at all. Other crimes once prevalent in common law jurisdictions—such as adultery， fornication， sodomy， and blasphemy—have been eliminated by many legislatures. These activities are often ignored by law enforcementofficials in jurisdictions where they remain crimes.
Lawmaking authority
The United States has a federal system of government， meaning that power is divided between a central authority and many regional authorities （ Federalism） . Consequently the power to make law， including criminal law， is divided between the national government and the governments of the50 states. Local governments also have the authority to enact laws.
The federal government derives its legislative power from the Constitution of the United States. The Constitution gives the federal government authority over certain limited subjects， such as the power to tax， to regulate interstate commerce， to declare war， and to regulate the mail. These powers include an implied authority to define some crimes. For example， the taxation power includes the authority to make it a crime to fail to file an income-tax return or to understate income in a return that is filed. The authority over mail includes the implied power to make it a crime to use the mail to defraud（ cheat by deception） or to distribute obscene publications.
The Constitution also explicitly grants power to define criminal behavior. For example， it gives the federal government the authority to punish counterfeiting， treason， and felonies committed on the high seas （ such as piracy） and to govern land areas in the United States devoted to federal uses， such as military bases and national parks. The federal government may also protect itself from harm. Thus it has defined as crimes sedition （ inciting dissatisfaction with government） ， bribery of federal officials， and perjury （ providing false testimony） in federal courts. In federal territories， the federal government has substantial power over criminal matters， a power similar to that retained by states within their own borders.