The exclusionary rule, which keeps evidence seized in violation of the Fourth Amendment out of criminal trials, is a prudential rule, not one commanded by the Constitution.  It is applied mainly when the government seeks to use the illegally obtained evidence to incriminate the victim of the illegal search and seizure.  When the rule’s application would not serve its deterrent purpose or when its benefits outweigh its social cost, it is not applied.  Here, the court refuses to apply the exclusionary rule to bar admission of illegally seized evidence to support a policeman’s defense to a 1983 suit for false, warrantless arrest.

Ninth Circuit Court of Appeals (O’Scannlain, J.); June 27, 2016; 2016 WL 3525209