Which Supreme Court case established the Exclusionary Rule restricting admissibility of illegally obtained evidence?

• A. Mapp v. Ohio
• B. Gideon v. Wainwright
• C. Miranda v. Arizona
• D. Heller v. District of Columbia

Answer: (A)

The Exclusionary Rule protects Fourth Amendment rights by barring the use of evidence obtained through illegal searches or seizures. This rule was first applied to federal courts in Weeks v. United States, but it was extended to state courts to ensure nationwide protection through incorporation of the Fourth Amendment via the Fourteenth Amendment in Mapp v. Ohio. That decision made illegally obtained evidence inadmissible in both federal and state prosecutions, which is why it’s the best answer. The other cases concern different protections—right to counsel, Miranda warnings, or gun rights—so they don’t establish the exclusion of illegally obtained evidence.