Whether evidence obtained by state officers through an unreasonable search or seizure, without federal participation, may be admitted over a timely objection in a federal criminal trial.
Holding
No. The Court abolished the silver platter doctrine: evidence seized by state officers in a search that would violate the Fourth Amendment if federal officers had conducted it is inadmissible in a federal criminal prosecution.
Reasoning
Weeks v. United States had long excluded evidence obtained by federal officers in violation of the Fourth Amendment, while also stating that the Amendment did not reach misconduct by state officers acting alone. That latter proposition supported the silver platter doctrine. But Wolf v. Colorado later held that the Fourteenth Amendment protects people against arbitrary state searches and seizures. Once state officers' unreasonable searches also violate federally protected rights, there is no principled basis for a federal court to distinguish evidence based solely on whether the unconstitutional officer wore a federal or state badge.
The Court treated exclusion as an exercise of its supervisory authority over federal criminal justice, rather than as an automatic rule of evidentiary relevance. The exclusionary rule's purpose is preventive: by denying the government the evidentiary benefit of unlawful conduct, it removes an incentive to disregard constitutional limits. The rule protects not only defendants whose incriminating evidence is found, but also innocent people whose unlawful searches produce nothing and are therefore unlikely to generate a practical remedy.
Experience did not show that exclusion would cripple law enforcement. Federal courts had operated under the Weeks rule for decades, and many states had adopted exclusionary rules in whole or in part. The Court also concluded that a uniform federal exclusion rule would improve federal-state relations: it would not undermine a state's own policy of suppressing unlawfully seized evidence, and it would eliminate incentives for federal agents to evade constitutional standards by relying on independent state misconduct.
Judicial integrity supplied an additional basis for the rule. Federal courts, sworn to uphold the Constitution, should not become accomplices in the use of evidence procured through a willful constitutional violation. A government that prosecutes crime while benefiting from unlawful searches teaches that official ends justify unlawful means.