In Benanti v. United States (1957), the Supreme Court ruled on the admissibility of evidence obtained through wiretapping by state law enforcement officials and later used in federal court. The defendants, Peter Benanti and Joseph Carlino, were convicted for conspiracy to rob a federally insured bank based on such evidence. They argued that this violated their Fourth Amendment rights against unreasonable searches and seizures as well as their Fifth Amendment right against self-incrimination. However, the Supreme Court held that since there was no federal involvement in obtaining the wiretap evidence, it did not violate either amendment under existing precedents at that time which allowed use of illegally seized evidence if done so without federal participation or direction. Therefore, even though New York State's actions may have been illegal under its own laws regarding unauthorized wiretaps by private citizens or police officers acting outside official duties - they didn't infringe upon constitutional protections because those only applied to government action.

In the dissenting opinion for Benanti v. United States, Justice Brennan disagreed with the majority's interpretation of Section 605 of the Federal Communications Act. He argued that Congress intended to protect all conversations from interception and disclosure, not just those involving innocent parties. According to him, this protection should also extend to guilty parties involved in illegal activities over telephone lines because it is a matter of privacy rights rather than guilt or innocence. Furthermore, he contended that allowing law enforcement officials to intercept and disclose these communications without any restrictions could lead to potential abuses of power. Therefore, he believed that such interceptions should only be permitted under specific circumstances outlined by Congress rather than being left up entirely to judicial discretion.