In the Supreme Court case of Matt vs. Ohio, what rule was applied to state courts?

In the Supreme Court case of Mapp v. Ohio, the ruling established the exclusionary rule as applicable to state courts. This landmark decision extended the protections against unreasonable searches and seizures guaranteed by the Fourth Amendment of the Constitution. The exclusionary rule mandates that evidence obtained in violation of a defendant's constitutional rights cannot be used in court.

Prior to the ruling, the exclusionary rule was primarily applied at the federal level, meaning that evidence obtained unlawfully by federal law enforcement could not be used in federal trials. Mapp v. Ohio incorporated this principle and applied it to state courts as well, which meant that any evidence obtained through illegal searches would also be inadmissible in state prosecutions. This was a significant expansion of the rights of defendants in the criminal justice system, emphasizing the importance of due process at both the state and federal levels.