Missouri Legislature
Missouri, a state of denial
Missouri, a state of denial

The notion that states can decide for themselves whether federal laws are unconstitutional — a doctrine known as nullification — is rejected even by many legal scholars who support states' rights. But this week it came within one vote of being adopted by the state Legislature in Missouri, and supporters of the idea there and elsewhere say they will continue their campaign to "nullify" federal gun laws. According to Article VI of the U.S. Constitution, that document "and the laws of the United States which shall be made in pursuance thereof … shall be the supreme law of the land." But in May, the Missouri Legislature approved what it called the...