However, Cheek's statutory argument—his asserted belief that his wages were not income under the statute (the Internal Revenue Code itself)—was ruled by the Supreme Court to be a possible ground for a valid defense even though that belief was not objectively reasonable, provided that the belief was actually held in good faith. The Supreme Court ruled that by instructing the jury that the defendant's statutory argument had to be based on a belief that was "objectively reasonable," the trial judge had erroneously transformed what should have been treated as a "factual issue" (for the jury to decide) into a "legal issue". The Supreme Court stated that whether the defendant acted willfully is a factual issue to be determined by the jury, and that a valid defense of "lack of willfulness" could be found even though the defendant's belief is not "objectively reasonable." The Supreme Court remanded the case to the trial court for a retrial. The Court also provided guidelines that could be used by the jury at the retrial: