In the case of Umans v. United States (1967), the defendant, Umans, was convicted for failing to report income from illegal gambling operations on his federal tax returns. He appealed this conviction arguing that he had been compelled to incriminate himself in violation of the Fifth Amendment by being forced to disclose an unlawful source of income on his tax return. The Supreme Court rejected this argument and upheld his conviction stating that there is no constitutional right for a taxpayer not to file a return which might reveal illegal activities as long as it does not require him/her specifically to disclose any information relating directly or indirectly with violations of law other than those related with taxes themselves.

In the dissenting opinion for Umans v. United States, Justice Fortas argued that the majority's decision to uphold a conviction based on evidence obtained through wiretapping was inconsistent with previous Supreme Court rulings and infringed upon Fourth Amendment protections against unreasonable searches and seizures. He contended that wiretapping constituted an invasion of privacy even if it was used to gather evidence in a criminal investigation. Furthermore, he disagreed with the majority's assertion that consent from one party involved in a conversation made such surveillance lawful, arguing instead that both parties must give their consent before their communications can be legally intercepted. In his view, this case represented an unwarranted expansion of government power at the expense of individual liberties.