Cheek v. united states: facts: defendant, a professional pilot, was convicted under 26 u. s. c. 7201 which provides that any person is guilty of a felony that willfully attempts in any manner to evade or defeat any tax imposed by this title or payment thereof. Defendant had failed to file a tax return required by law and argued in his defense that his failure to file was based on information he received from a group opposing the institution of taxation. Based on this information, defendant asserted that he believed that he owed no taxes, including taxes on his wages. At trial the judge instructed the jury that an honest but unreasonable belief is not a defense and does not negate willfulness. However, the statutes of tax law sometime make it difficult for the average citizen to know the extent of his/her duties under tax law.