What landmark case established the Exclusionary Rule at the federal level?

The landmark case that established the Exclusionary Rule at the federal level is Weeks v. United States. This decision, rendered in 1914, was pivotal because it ruled that evidence obtained through illegal searches and seizures in violation of the Fourth Amendment could not be used in federal prosecutions. This case set the precedent that law enforcement must adhere to constitutional protections when gathering evidence, emphasizing that illegally obtained evidence undermines the integrity of the judicial system.

While Wolfe v. Colorado did address the application of the Fourth Amendment concerning state courts, it did not establish the Exclusionary Rule. Mapp v. Ohio later extended the Exclusionary Rule to state courts, but it was Weeks that established it at the federal level. Similarly, Miranda v. Arizona focused on the rights of individuals during police interrogation and the requirement of informing suspects of their rights, but it is not directly related to the Exclusionary Rule itself. Thus, Weeks v. United States is the correct answer for establishing the Exclusionary Rule at the federal level.