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. The law amounts to the most far-reaching states’ rights endeavor in the country, the far edge of a growing movement known as ‘nullification’ in which a state defies federal power. In a letter explaining his veto, Governor Jay Nixon said the federal government’s supremacy over the states’ ‘is as logically sound as it is legally well established.’ When the legislature gathers again, it will seek to override his veto.