Which case extended the Exclusionary Rule to protect defendants in state cases?

• A. Weeks v. US
• B. Mapp v. Ohio
• C. Wolfe v. Colorado
• D. Miranda v. Arizona

Answer: (B)

Mapp v. Ohio is significant because it was the pivotal case that extended the Exclusionary Rule to state courts, thus providing constitutional protection against unlawful searches and seizures for defendants at the state level. Prior to this case, the Exclusionary Rule, which prohibits the use of evidence obtained through violating the Fourth Amendment, was primarily applicable to federal cases only.

In Mapp v. Ohio, the Supreme Court ruled that evidence obtained in violation of the Fourth Amendment rights of the defendant cannot be used in state law criminal prosecutions. This decision effectively incorporated the Fourth Amendment protections through the Fourteenth Amendment's Due Process Clause, ensuring that all states are held to the same standards regarding the admissibility of evidence.

This case built upon earlier rulings, but it was Mapp that firmly established that state courts must also adhere to the principles of the Exclusionary Rule, thus reinforcing the Fourth Amendment's protections across the United States. The ruling has had a lasting influence on how evidence is treated in both state and federal criminal proceedings.