Officially titled "An Act to Organize the Territories of Nebraska and Kansas", the Kansas-Nebraska Act repealed the Missouri Compromise, allowing slavery in the territory north of the 36° 30´ latitude. Introduced by Senator Stephen Douglas of Illinois, the Kansas-Nebraska Act stipulated that the issue of slavery would be decided by the residents of each territory, a concept known as popular sovereignty. After the bill passed on May 30, 1854, violence erupted in Kansas between pro-slavery and anti-slavery settlers, a prelude to the Civil War.