In the 1962 case of Lopez v. United States, the Supreme Court ruled that a secret recording made by an Internal Revenue Service (IRS) agent could be used as evidence in court. The defendant, Irving H. Lopez, was accused of attempting to bribe an IRS agent during a tax investigation into his business affairs. During their conversation, which took place in Lopez's office and without his knowledge or consent, the IRS agent recorded their discussion using a concealed device. This recording was later presented as key evidence against him at trial where he was convicted for bribery. Lopez appealed this decision on grounds that it violated his Fourth Amendment rights against unreasonable searches and seizures but also Fifth Amendment right not to incriminate himself involuntarily; however, both arguments were rejected by the Supreme Court who upheld his conviction with a 5-4 majority vote. The justices concluded that since there had been no physical intrusion into any space considered private under Fourth Amendment protections - such as home or office - nor coercion forcing self-incrimination under Fifth Amendment protections then neither constitutional rights were breached hence ruling out exclusionary rule application.

In the dissenting opinion for Lopez v. United States, Justice William O. Douglas argued that the use of a recording device by an IRS agent constituted a violation of the Fourth Amendment's protection against unreasonable searches and seizures. He contended that such surreptitious recordings were akin to wiretapping, which had been previously ruled unconstitutional in certain contexts. Furthermore, he believed this case represented an overreach by law enforcement officials who could potentially abuse their power if allowed to record private conversations without consent or warrant. In his view, allowing such practices would undermine citizens' rights to privacy and due process under law.