The election of Abraham Lincoln split the United States tremendously. With the election of Lincoln, southerners feared that their way of life was in danger. They felt that Lincoln's election would eventual result in outlawing the institution of slavery.
This fear caused southern states to take dramatic action. Roughly one month after the election of Lincoln, South Carolina seceded (left) the United States. After South Carolina, states like Florida, Alabama, and Mississippi seceded as well. Ultimately the secession of states like this resulted in the creation of the Confederate States of America, which sets the scene for the Civil War.