Lincoln was elected on November 6, 1860. The south flipped out. Of course, many of the states had already been plotting treason in the event of a Republican presidential victory, some going back as early as 1858. Following the election, southern states began forcibly seizing federal property in the south. By the time of the inauguration, on March 4, 1861, only Fort Sumter and Fort Pickens remained in federal hands. The new administration tried negotiating, offering slave states an amendment to the constitution preserving slavery where it legally existed. Not good enough. On March 4, 1861, in his inaugural address to the nation, Lincoln promised to hold only federal property that was still in possession of the United States as of that date. Not good enough. The south was determined to go to war. Of course, South Carolina had already been trying to seize Fort Sumter, but it was held by determined soldiers. SC had demanded its surrender from lame duck President Buchanan as early as December, and was demanding the soldiers inside surrender as early as January. The first shots of the civil war were actually fired in January of 1861, not April, as cadets from The Citadel fired on The Star of the West, sent to resupply the besieged troops. A more concerted and heavily armed resupply effort was attempted by the United States in April. The first ship arrived on April 11. SC opened fire on April 12. So, as you can see, southerners were simply defending themselves from an invasion by aggressive northerners.