What does the exclusionary rule, established by Mapp v. Ohio, do?

The exclusionary rule, established by the landmark Supreme Court case Mapp v. Ohio, requires that incriminating evidence obtained through illegal searches and seizures be excluded from being presented in court. This means that if law enforcement officials gather evidence in violation of a person's Fourth Amendment rights—such as through an unlawful search or without a valid warrant—that evidence cannot be used against the defendant in a criminal trial.

This rule is crucial as it serves to deter law enforcement from violating constitutional rights, thereby upholding the integrity of the judicial process. The Mapp decision extended the exclusionary rule to state courts, reinforcing that all individuals, regardless of state jurisdiction, are protected against unreasonable searches and seizures. This protective measure underscores the importance of due process and the respect for individual rights within the American legal framework.