2018 ruling. I wonder if ot held up. And the men were actually sort of let off. "The men challenged the constitutionality of the National Firearms Act, alleging it is an invalid exercise of congressional power and an invasion of the Second Amendment right to bear arms. They also challenged the lower court’s ruling that their reliance on the state law provided no defense to the federal charges. Separately, Kettler argued further that his prosecution resulted from the dispute between Kansas and the federal government over the Kansas law. The appeals court panel rejected all the defense arguments in a 47-page decision. It concluded the federal gun law falls within Congress’ power to tax. The court also noted that the men’s reliance on the state mitigated their sentences, if not their guilt. It noted the district court took their mistaken reliance on the state law into consideration when it sentenced them to probation." Edit. At supreme court. What happened? https://www.supremecourt.gov/DocketPDF/18/18-936/80448/20190114152050390_Kettler%20Petition%20for%20Certiorari.pdf