The correct answer is "President Lincoln called for 75,000 volunteers to enlist". On April 12, 1861, the first cannon shot of the Civil War was shot in Fort Sumter, located in Charleston Bay (South Carolina). This battle was the first confrontation of a war that would last four years and that would cost the lives of more than 500,000 Americans. Six days after South Carolina declared its independence from the Union, Major Robert Anderson moved his troops in secret to Fort Sumter to offer resistance to the southern armies. Anderson's decision was received by the northern states as an evidence of patriotism. The southern states interpreted it as a call to war. On April 12 they started a bombing against the troops of Anderson, and two days later they manage to take the bastion. After the defeat, President Lincoln on April 15 called for 75,000 volunteers to enlist. This call caused that the undecided states to take their positions. The result was that the North (Union) was composed of 23 states, while the South (Confederation) of 11. Both sides would fight until 1865 when the Union won.