Exclusionary rule

Exclusionary rule, in U.S. law, the principle that evidence seized by police in violation of the Fourth Amendment to the U.S. Constitution may not be used against a criminal defendant at trial. The Fourth Amendment guarantees freedom from unreasonable searches and seizures—that is, those made without a warrant signed by a judge. The U.S. Supreme Court held in Wolf v. Colorado (1949) that “security of one’s privacy against arbitrary intrusion by the police—which is at...