Good-Faith Exception

The good-faith exception is a limitation on the exclusionary rule in United States Fourth Amendment law that allows evidence obtained under a defective search warrant to be used at trial if the officers who executed it relied in good faith on the validity of the warrant. The exclusionary rule itself traces to Weeks v. United States in 1914, which barred illegally obtained evidence from federal prosecutions, but the good-faith exception was not established until 1984 in United States v. Leon and its companion case Massachusetts v. Sheppard. Courts apply an objective standard, asking whether the officers had a reasonable basis to believe their conduct was constitutional, typically because they relied on a warrant issued by a neutral magistrate or a statute later found invalid. The exception does not apply when a warrant was obtained through deliberately false information, when the issuing judge was not neutral, when probable cause was clearly lacking, or when the warrant was so deficient in describing the place or items that officers could not reasonably presume it valid; the Court reasoned that suppressing evidence in these narrower situations does not deter police misconduct that was never present.