The document discusses the growing sectionalism between the North and South in the United States leading up to the Civil War. Key events that exacerbated tensions included the Missouri Compromise of 1820, the Kansas-Nebraska Act of 1854, and the election of Abraham Lincoln in 1860, which prompted several Southern states to secede and form the Confederate States of America. The document aims to explain the political, economic, and social divisions between free and slave states that ultimately led the nation to civil war.