Memory Game Causes for the Civil WarOnline version Identify the causes that led to the American Civil War. by Andrew Balzer 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 Popular Sovereignty Sectionalism Let the people of the territories themselves decide whether slavery would be permitted. Compromise of 1850 Kansas-Nebraska Act It allowed people in the territories of Kansas and Nebraska to decide for themselves whether or not to allow slavery within their borders. It required that all escaped slaves, upon capture, be returned to their masters and that officials and citizens of free states had to cooperate. Novel written by Harriet Beecher Stowe that showed the horrors of slavery. Fugitive Slave Law Uncle Tom's Cabin