Instead of coming to terms with each other in a suitable fashion, sectionalism drove each person to be "a member of their state", instead of being a "american". This led to conflicting interests, which boiled down to war. Each person went to war for reasons of their state, instead of what Lincoln wanted, the preservation of the Union.
Missouri Compromise, measure worked out in 1820 between the North and the South and passed by the U.S. Congress that allowed for admission of Missouri as the 24th state. It marked the beginning of the prolonged sectional conflict over the extension of slavery that led to the American Civil War.
