Laws allowing gun owners to openly carry firearms in public are set by each state. Thirty-one states allow open carry without a special license or permit; fifteen states allow open carry with a special license or permit.
Federal firearms legislation includes the National Firearms Act, prohibiting the transfer or possession of certain firearms, like machine guns, and the Brady Law, which mandates background checks for certain gun transactions. Another U.S. law forbids carrying firearms, open or concealed, on federal property.
In a 1997 ruling related to some Brady Law provisions, the Supreme Court said that "the Federal Government may not compel the States to enact or administer a federal regulatory program."