On the eve of the American Civil War, the major historical event was the election of Abraham Lincoln as President of the United States in 1860. His election prompted a seismic shift in the political landscape, as many Southern states viewed Lincoln's anti-slavery stance as a direct threat to their way of life. Following Lincoln's election, South Carolina seceded from the Union in December 1860, leading to the establishment of the Confederate States of America. This escalating tension over issues like states' rights and slavery ultimately culminated in the outbreak of the Civil War in April 1861.