In Panico v. United States, 1963, the defendant Joseph Panico was convicted of tax evasion for not reporting income from illegal gambling operations in his federal income tax returns. The Supreme Court upheld the conviction despite Panico's argument that he should have been protected by the Fifth Amendment against self-incrimination because any admission of illegal activity could potentially lead to criminal prosecution. The court ruled that there is no constitutional right to evade taxes on illegally earned income and rejected his claim stating that if a taxpayer desires not to disclose incriminating information, they must claim their privilege against self-incrimination on their return rather than simply omitting or falsifying information about such activities.

In the dissenting opinion for Panico v. United States, Justice Harlan argued that the majority's decision to reverse Panico's conviction was incorrect because it failed to consider important aspects of the case. He believed that there was sufficient evidence presented at trial to support a finding of guilt beyond reasonable doubt and disagreed with the majority’s interpretation of "willfulness" in tax evasion cases. According to him, willful intent can be inferred from conduct aimed at concealing income or misleading authorities about one’s financial status. Furthermore, he criticized the majority for not giving due weightage to jury instructions which clearly defined 'willfulness' as an intentional violation of a known legal duty and explained how circumstantial evidence could be used in proving this element. In his view, these instructions provided adequate guidance on law and left no room for confusion among jurors regarding what they needed to find in order to convict Panico under federal tax laws.