Sectionalism: Refers to loyalty or support for one's own region or section of a country rather than the whole nation.
Nullification Crisis: A political crisis in 1832 when South Carolina attempted to nullify federal tariffs imposed by Congress, highlighting tensions between states' rights and federal authority.
Kansas-Nebraska Act: A controversial law passed in 1854 that allowed popular sovereignty (allowing residents of territories to decide whether they would allow slavery), further intensifying sectional divisions.