Creates the inevitable discovery exception to the Fourth Amendment, under which evidence that might otherwise be suppressed as unconstitutionally obtained can be included if the state can demonstrate that it would reasonably have been found in any event. Decided June 11, 1984 (argued January 18, 1984). Opinion of the Court: Warren E. Burger → go there Dissenting: Brennan. Applied: the Fourth Amendment → go there Topic: Fourth Amendment rights. Nix v. Williams, 467 U.S. 431 (1984), was a U.S. Supreme Court case that recognized an "inevitable discovery" exception to the exclusionary rule. The exclusionary rule makes some evidence gathered through violations of the Fourth Amendment to the United States Constitution, which protects against unreasonable search and seizure, inadmissible in criminal trials as "fruit of the poisonous tree". In Nix, the Court ruled that evidence that would inevitably have been discovered by law enforcement through legal means remained admissible. Wiki link