Nullification

Nullification grew from the Kentucky Resolutions of 1798, in which Thomas Jefferson argued that states could declare void federal laws exceeding the Constitution, such as the Alien and Sedition Acts. John C. Calhoun of South Carolina developed the theory in his anonymous South Carolina Exposition and Protest of 1828, written against the high protective tariff that Southerners called the Tariff of Abominations. Calhoun argued that the Constitution was a compact among sovereign states and that a state convention could block enforcement of an unconstitutional federal law within the state.

On November 24, 1832, a South Carolina convention declared the tariffs of 1828 and 1832 null and void and threatened secession if the federal government used force. President Andrew Jackson responded with a proclamation on December 10, 1832, calling nullification incompatible with the existence of the union, and Congress passed the Force Bill authorizing military action along with a compromise tariff on March 2, 1833. South Carolina repealed its ordinance, then symbolically nullified the Force Bill. The crisis foreshadowed the secession debates of 1860.

Northern states used nullification-like resistance against the Fugitive Slave Act, which the Supreme Court rejected in Ableman v. Booth in 1859, and Southern states claimed a right of interposition against school desegregation in the 1950s, which the Court rejected in Cooper v. Aaron in 1958. Some states have since passed laws declaring certain federal gun laws unenforceable, and federal courts struck down Missouri's Second Amendment Preservation Act in 2023. Courts hold that the Supremacy Clause leaves no room for nullification, though states may lawfully decline to help enforce federal laws under the anti-commandeering doctrine.