A proponent of westward expansion and a prominent proslavery Democrat in the state of Missouri, David Rice Atchison led the call for slavery’s extension into the Kansas and Nebraska territories. Following the passage of the divisive Kansas-Nebraska Act in 1854, Atchison directed efforts of Missourians to cross the border in order to stuff ballots during Kansas’ first territorial election in 1855 and personally led Missouri “border ruffians” in their often-violent efforts to secure Kansas as a slave state, including an attack on Lawrence, Kansas in 1856.