In the United States v. Fabrizio case in 1966, the Supreme Court dealt with issues related to tax evasion and fraud. The defendant, Mr. Fabrizio was accused of evading taxes by underreporting his income from illegal gambling operations for three years (1957-1959). He argued that he had not committed any crime because he had reported all his legal income correctly and did not have a legal obligation to report money earned through illegal activities due to Fifth Amendment protections against self-incrimination. However, the court rejected this argument stating that regardless of how it was earned, all income is taxable under U.S law and must be reported accurately on tax returns. Therefore, failure to do so constitutes tax evasion which is punishable by law irrespective of whether or not reporting such earnings would incriminate oneself in other crimes.

The dissenting opinion in the United States v. Fabrizio case argued that the majority's decision to uphold Fabrizio's conviction for failing to answer questions before a grand jury was flawed. The dissent contended that Fabrizio had not been adequately informed of his rights, including his right against self-incrimination under the Fifth Amendment, prior to testifying before the grand jury. They believed this lack of information constituted a violation of due process and should have resulted in overturning his conviction. Additionally, they disagreed with the majority's interpretation of "willfully" as used in 18 U.S.C §192 (the statute under which Fabrizio was charged), arguing it required proof that he intentionally sought to obstruct justice by refusing to answer questions rather than simply knowing he was legally obligated but choosing not to comply.