Byron White, Cheek v. United States — Opinion of the Court
“ Characterizing a particular belief as not objectively reasonable transforms the inquiry into a legal one and would prevent the jury from considering it. It would of course be proper to exclude evidence having no relevance or probative value with respect to willfulness; but it is not contrary to common sense, let alone impossible, for a defendant to be ignorant of his duty based on an irrational belief that he has no duty, and forbidding the jury to consider evidence that might negate willfulness would raise a serious question under the Sixth Amendment's jury trial provision. ”
