The Nullification Crisis ended in 1833 when the two sides reached an agreement on a new tariff. The crisis started when South Carolina leaders began promoting the idea that states need not follow federal laws and could nullify them.
Politician John C. Calhoun was a primary promoter of the concept of states' rights. The idea of nullification was a precursor to the later secession crisis that triggered the Civil War.
An 1828 tariff that raised import taxes angered Calhoun and other South Carolina political leaders. The controversial tariff became known as the Tariff of Abominations in some parts of the United States. Before the issue was resolved, armed conflict seemed possible if South Carolina attempted to secede.