1. Secession
2. December 20

Convinced that a Republican administration would attempt to undermine slavery by appointing antislavery judges, postmasters, military officers, and other officials, a secession convention in South Carolina voted unanimously to secede from the Union on December 20, 1860. Drawing on arguments developed by John C. Calhoun, the convention held that the states were sovereign entities that could leave the Union as freely as they joined.