The immediate cause of secession for southern states before the Civil War was the election of Abraham Lincoln as president in November 1860. Lincoln's victory represented the growing political power of the Republican Party, which was seen by many southerners as hostile to their interests, particularly on the issue of slavery. The Republican Party platform called for the opposition to the extension of slavery into new territories, which many southerners feared would eventually lead to the abolition of slavery in the existing southern states.
South Carolina was the first state to secede from the Union on December 20, 1860, followed by Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas in early 1861. These seven states formed the Confederate States of America, with Jefferson Davis as its president. The seceding states cited their right to self-determination and the preservation of their institution of slavery as their reasons for leaving the Union.