Memory Causes for the Civil WarVersion en ligne Identify the causes that led to the American Civil War. par Andrew Balzer Uncle Tom's Cabin Popular Sovereignty Kansas-Nebraska Act It required that all escaped slaves, upon capture, be returned to their masters and that officials and citizens of free states had to cooperate. Fugitive Slave Law Let the people of the territories themselves decide whether slavery would be permitted. Novel written by Harriet Beecher Stowe that showed the horrors of slavery. It allowed people in the territories of Kansas and Nebraska to decide for themselves whether or not to allow slavery within their borders. loyalty to one's own region or section of the country, rather than to the country as a whole California entered as a free state Sectionalism Compromise of 1850