The Gibson v. United States case in 1946 revolved around the issue of whether or not a person could be prosecuted for refusing to testify before a grand jury, even if they were granted immunity from prosecution based on their testimony. The defendant, Gibson, was subpoenaed by a federal grand jury investigating violations of internal revenue laws but refused to answer questions about his income and sources thereof citing self-incrimination protection under the Fifth Amendment. He was then granted immunity under federal law but still refused to testify and was subsequently held in contempt of court and sentenced to imprisonment. Upon appeal, the Supreme Court upheld this decision stating that once immunity is provided equivalent to the constitutional privilege against self-incincrimination (as it had been), there can be no basis for refusal to comply with an order requiring one's testimony.

In the dissenting opinion for Gibson v. United States, Justice Murphy argued that the majority's decision to uphold a conviction based on evidence obtained through wiretapping was fundamentally flawed. He contended that such methods of obtaining evidence were not only illegal but also violated basic principles of justice and fairness. Furthermore, he expressed concern about the potential misuse of wiretapping by law enforcement agencies and warned against allowing such practices to become normalized in criminal investigations. In his view, permitting convictions based on illegally obtained evidence would undermine public trust in the legal system and could potentially lead to abuses of power by law enforcement officials.