What is the "exclusionary rule"?

The exclusionary rule is a legal principle that prohibits the use of evidence in a criminal trial if it was obtained in violation of the defendant's constitutional rights, particularly the Fourth Amendment, which guards against unreasonable searches and seizures. This rule was established to deter law enforcement from conducting illegal searches and to uphold the integrity of the judicial system. By ensuring that illegally obtained evidence cannot be used in court, the exclusionary rule helps protect individuals' rights and promotes lawful enforcement of the law.

This principle emphasizes the importance of adhering to constitutional protections and reinforces the idea that justice should not only be done but should also be seen to be done. In practice, it means that if police obtain evidence through methods that violate a person’s right to privacy—such as without a warrant or probable cause—that evidence cannot be presented in court, potentially leading to the dismissal of the charges against the defendant.