In Hoffa v. United States (1966), the U.S Supreme Court upheld the conviction of Jimmy Hoffa, then-president of the International Brotherhood of Teamsters, for jury tampering. The case revolved around whether or not a government informant's presence in Hoffa's hotel suite constituted an illegal search and seizure under the Fourth Amendment. Edward Partin, a fellow union member who was also a paid FBI informant, had been invited into Hoffa’s suite where he overheard conversations about plans to bribe jurors in another trial involving Hoffa. The court ruled 7-2 that since Partin had been invited into the room by Hoffa himself and did not conduct any physical search or seizure while there, no violation occurred. Furthermore, they held that one assumes risk when revealing incriminating information to others - even if those individuals turn out to be government informants.

In the dissenting opinion for Hoffa v. United States, Justice William O. Douglas argued that the government's use of an informant violated Jimmy Hoffa's Fourth Amendment rights to privacy and his Fifth Amendment right against self-incrimination. He contended that Partin, a paid government informant who had infiltrated Hoffa’s inner circle under false pretenses, acted as an agent of the state when he gathered evidence against Hoffa without a warrant or probable cause. This constituted illegal search and seizure in violation of the Fourth Amendment according to Douglas' interpretation. Furthermore, he believed this method was essentially compelling Hoffa to incriminate himself by trickery which is prohibited by the Fifth Amendment protection against self-incrimination.