Unless a handful of wavering Democrats change their minds, the Republican-controlled Missouri legislature is expected to enact a statute next month nullifying all federal gun laws in the state and making it a crime for federal agents to enforce them here.
A Missourian arrested under federal firearm statutes would even be able to sue the arresting officer.
http://www.nytimes.com/2013/08/29/us/missouri-gun-measure-pushes-nullification-boundary.html?google_editors_picks=true&_r=0