Which important Supreme Court case established the exclusionary rule regarding illegally obtained evidence?

The case that established the exclusionary rule regarding illegally obtained evidence is Mapp v. Ohio. In this landmark 1961 decision, the Supreme Court held that evidence obtained in violation of the Fourth Amendment, which protects against unreasonable searches and seizures, cannot be used in state courts. This ruling is significant because it extends the exclusionary rule, which was previously applied only to federal cases, to state jurisdictions as well.

The court's decision in Mapp v. Ohio arose from a situation where police had entered the home of Dollree Mapp without a proper search warrant and seized materials that were used to convict her. The Supreme Court found that not only was the search improper, but the evidence obtained as a result was inadmissible in court. This decision reinforced the protection of individual rights against unlawful treatment by law enforcement, underscoring the importance of due process in the judicial system.

In contrast, the other cases listed involve different legal principles. Miranda v. Arizona relates to the rights of individuals during custodial interrogations. Gideon v. Wainwright addresses the right to legal counsel in state courts. New Jersey v. T.L.O. deals with search and seizure in school environments. None of these cases established the exclusionary rule