The Kansas-Nebraska Act was an 1854 bill that mandated “popular sovereignty”–allowing settlers of a territory to decide whether slavery would be allowed within a new state’s borders. Proposed by Stephen A. Douglas–Abraham Lincoln’s opponent in the influential Lincoln-Douglas debates–the bill overturned the Missouri Compromise’s use of latitude as the boundary between slave and free territory. The conflicts that arose between pro-slavery and anti-slavery settlers in the aftermath of the act’s passage led to the period of violence known as Bleeding Kansas, and helped paved the way for the American Civil War (1861-65).
