The defendants Jack Miller and Frank Layton were indicted on charges of unlawfully and feloniously transporting in interstate commerce from Oklahoma to Arkansas an unregistered double barrel 12-gauge shot gun having a barrel less than 18 inches in length, in violation of the National Firearms Act, 26 U.S.C.S. § 1132c et seq. ("Act"). At trial in federal district court, the defendants filed a demurrer to the indictment alleging that the Act was not a revenue measure but an attempt to usurp police power reserved to the states and so was unconstitutional. Defendants further argued that the Act violated the Second Amendment to the United States Constitution. The district court held that the section of the Act that made it unlawful to transport an unregistered firearm in interstate commerce was unconstitutional as violative of the Second Amendment. It accordingly sustained the demurrer and quashed the indictment. The government took a direct appeal to the Supreme Court.