Mapp v. Ohio established the Exclusionary Rule prohibiting evidence obtained in violation of the Fourth Amendment in which courts?

• A. Federal courts only
• B. State and federal courts
• C. State courts only
• D. Civil courts only

Answer: (B)

The Exclusionary Rule, which bars evidence obtained through unreasonable searches or seizures from being used in court, applies to both state and federal courts. Mapp v. Ohio held that Fourth Amendment protections are incorporated against the states through the Fourteenth Amendment, so illegally obtained evidence cannot be used in state criminal prosecutions just as it cannot be used in federal prosecutions. This extended the rule beyond federal courts alone and standardized constitutional protections across jurisdictions. It’s not limited to civil courts, and the essential idea is that both state and federal courts must exclude unlawfully obtained evidence.