Cheek v. U.S.
Facts: Cheek was an airline pilot who didn't pay taxes for a number of years. He was convicted of willfully failing to file a federal income tax return. He was also convicted for the misdemeanor offense of "willfully" failing to make a return required by law.
Procedural History: Initial jury instructions: (1) "an honest but unreasonable belief is not a defense and does not negate willfulness" (2) "advice or research resulting in the conclusion that wages of a privately employed person are not income or that the tax laws are unconstitutional is not objectively reasonable and cannot serve as the basis for a good faith misunderstanding of the law."
Issue: Is a good-faith misunderstanding of the law or a good-faith belief that one is not violating the law a valid defense?
Reasons: The instructions to the jury saying that "belief that the laws are unconstitutional wasn't a valid defense" was acceptable instruction. This is a matter of misunderstanding of (or disagreeing with) the law. The instructions saying that the "conclusion that wages of a privately employed person are not income wasn't a valid defense" wasn't acceptable instruction. This is a matter of mistake of fact.
Judgment: Remand for retrial.