In Hoffa et al. v. United States, the Supreme Court upheld the conviction of Jimmy Hoffa, then-president of the International Brotherhood of Teamsters union, for jury tampering in a federal court case against him in Nashville. The evidence used to convict Hoffa was obtained by Edward Partin, a government informant who had been invited into Hoffa's hotel suite and heard discussions about plans to bribe jurors. The defense argued that this constituted an illegal search under the Fourth Amendment as Partin was acting as an agent for law enforcement without probable cause or a warrant when he overheard these conversations. However, the Supreme Court ruled 5-4 that since Partin had been invited into the room by Hoffa himself and there were no trespassing issues involved with his presence there nor any coercion or deceit used to gain entry, his actions did not constitute an unlawful search or seizure.

In the dissenting opinion for Hoffa et al. v. United States, Justice William O. Douglas argued that the government's use of an informant to gather evidence violated Hoffa's Fourth Amendment rights against unreasonable searches and seizures as well as his Fifth Amendment right against self-incrimination. He contended that the majority ruling expanded governmental power in a way that threatened individual liberties, particularly regarding privacy expectations within one’s own home or hotel room - places where people should feel most secure from government intrusion. Furthermore, he expressed concern about potential abuses of this power by law enforcement agencies who could plant informants in any situation under the guise of investigating possible criminal activity without needing a warrant or probable cause to do so.