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 pave the way for the American Civil War (1861-65).
This 1854 bill to organize western territories became part of the political whirlwind of sectionalism and railroad building, splitting two major political parties and helping to create another, as well as worsening North-South relations
