Whether the district court can preclude a defendant from presenting evidence about the complexity in the civil tax code to defend against the government's allegation that he willfully violated the law

Congress , in creating criminal liability for tax law violations , made an exception to the general rule that ignorance of the law is no excuse. When the government prosecutes someone for violating the civil tax code, the government must prove willfulness —that the tax law was objectively clear, the defendant knew what was required, and they intentionally and voluntarily violated the law regardless. Cheek v. United States, 498 U.S. 192, 199– 200 (1991) . The question presented is: Whether the district court can preclude a defendant from presenting evidence about the complexity in the civil tax code to defend against the government’s allegation that he willfully violated the law.