In an opinion by Justice Byron White, the Court ruled that the defendant's belief that the tax laws were "unconstitutional" was not a defense, no matter how honestly that belief might have been held. To the contrary, Cheek's acknowledgement that his failure to file tax returns was based on a belief about "constitutionality" was viewed by the Supreme Court as possible evidence (1) of Cheek's "awareness" of the tax law itself (the Court stating that constitutional arguments reveal the taxpayer's "full knowledge of the provisions at issue and a studied conclusion, however wrong, that those provisions are invalid and unenforceable"), and (2) of the voluntary, intentional violation of a known legal duty imposed by the tax law.