US Government Guide: constitutional law

Decisions by judges, who interpret and apply the Constitution to specific cases, create constitutional law. For example, judicial interpretation of the meaning of general phrases in the Constitution, such as “due process of law” or “unreasonable searches and seizures” or “interstate commerce,” establishes constitutional law. In the United States, the Supreme Court plays a central role in developing constitutional law. In 1982, for instance, the Court decided in United States v. Ross that the 4th Amendment ban against “unreasonable searches and seizures” did not prevent police, under certain circumstances, from searching the contents of a car without a search warrant.