Interposition and nullification are related doctrines asserting that states can resist or refuse to enforce federal laws deemed unconstitutional. Interposition means a state can "interpose" its authority between the federal government and the people, blocking federal action. Nullification means a state can declare a federal law null and void within that state. Both ideas have been thoroughly rejected by courts and modern constitutional law, but they resurface periodically.
The nullification doctrine gained prominence in the antebellum South. John C. Calhoun argued states could nullify federal tariffs they opposed. The Nullification Crisis of 1832 escalated when South Carolina threatened to secede rather than comply with federal tariff law, nearly triggering civil war. In the 1950s, Southern governors and legislatures invoked interposition to resist federal desegregation orders after Brown v. Board of Education. Arkansas Governor Orval Faubus claimed the state could "interpose" its authority to block integration, deploying the National Guard to prevent Black students from entering Little Rock Central High School in 1957.
The Supreme Court definitively rejected these doctrines in Cooper v. Aaron (1958), ruling unanimously that no state official—governor, legislator, or judge—can nullify federal constitutional law. The Supremacy Clause of Article VI and the oaths state officials take to support the Constitution make federal law binding. Despite this clear rejection, nullification-style arguments occasionally resurface when states resist federal gun laws, immigration enforcement, or marijuana prohibition, though these arguments carry no legal force.
Understanding why nullification is unconstitutional is essential to understanding that the Constitution creates a binding national law states cannot escape through state-level declarations. It explains why states must follow Supreme Court rulings even when they strongly disagree.
People sometimes think states can refuse to enforce federal laws they disagree with. In practice, the Supremacy Clause makes federal law binding on all state officials, and courts have conclusively rejected nullification arguments.
Understanding why nullification is unconstitutional is essential to understanding that the Constitution creates a binding national law states cannot escape through state-level declarations. It explains why states must follow Supreme Court rulings even when they strongly disagree.
People sometimes think states can refuse to enforce federal laws they disagree with. In practice, the Supremacy Clause makes federal law binding on all state officials, and courts have conclusively rejected nullification arguments.