The Civil War started with President Lincoln's difficult decision. He had to wether let the Confederates take over the federal property, which would be the same as admitting that the states could leave the union. Or he could send troops to hold the forts, but then he might start a Civil War. By doing that he would also lose the support of eight of the states (All slave states) that hadn't withdrawn from the union yet.
When April had come, the Confederacy forced President Lincoln to make up his mind. By then, Confederate troops had controlled nearly all the forts and federal buildings. The union had only four forts: 3 in the Florida Coast, and fort Sumter in South Carolina. On April 11th, 1861, the Confederates demanded that the troops surrender Fort Sumter. But they refused. So for more than four years, the North fought the South in the Civil War. The South wanted to exist as an independent nation, but the North wanted to force the South into the Union. The civil War was also closely related with slavery. This was made clear when President Lincoln issued the emancipation proclamation. Throughout the North and South, many soldiers and civilians experienced much fighting and suffering. The armies were struggling in the first years of the war. But, the North's wonderful resources wore heavily on the South. By 1863, the South was finally in retreat. In about 1865, the South surrendered at the Appomattox Courthouse