In the United States v. Pomponio et al., 1976, the Supreme Court ruled that "willfulness" in tax evasion cases under federal law only requires proof of a voluntary and intentional violation of a known legal duty, not an evil motive or bad purpose. The case involved two brothers, William and Michael Pomponio who were indicted for willfully attempting to evade income taxes. They argued that their actions did not constitute "willful" behavior as they lacked any malicious intent or evil motive in evading taxes; rather they had relied on advice from lawyers and accountants regarding their tax obligations. However, the court rejected this argument stating that it was enough to show that defendants understood their legal obligation to pay taxes but intentionally chose not to do so.

In the case of United States v. Pomponio, there was no dissenting opinion recorded. The Supreme Court delivered a per curiam decision affirming the judgment of the Fourth Circuit Court of Appeals without any justice publicly expressing disagreement or offering an alternative viewpoint on the matter at hand.