The southern United States did indeed fight in a civil war, known as the American Civil War, which took place from 1861 to 1865. The conflict was primarily fought between the Northern states, which were loyal to the Union, and the Southern states, which had seceded and formed the Confederate States of America. The main cause of the war was the issue of slavery, with the Southern states seeking to preserve the institution of slavery while the Northern states were pushing for its abolition. The war resulted in a victory for the Union, the abolition of slavery, and the reunification of the United States.