Doctrine upholding the right of a U.S. state to declare null and void an act of the federal government. First enunciated in the Virginia and Kentucky Resolutions (1798), it was expanded by John C. Calhoun in response to the Tariff of 1828. Calhoun maintained that a state interposition could block enforcement of a federal law. The South Carolina legislature agreed by passing the Ordinance of Nullification (1832), threatening to secede if the federal government forced collection of the 1828 tariff duties. Pres. Andrew Jackson asserted the supremacy of the federal government. The U.S. Congress passed a compromise tariff bill reducing the duties but also passed the Force Bill, which authorized federal enforcement of the law. The South Carolina legislature rescinded its ordinance, but the conflict highlighted the danger of nullification.