Why did they fight?

Because the southern states disliked the way the government ran the country and believed in each state governing itself entirely where the government itself gave partial power to the states and held supreme power. After failing to convince the government to change, the Southern States attempted to succeed from the United States. When denied that by the government, they fired at Fort Sumpter and this act was considered a war declaration. Later in the war as stated below, the slavery issue became a part of what they fought for. But it boiled down to how the country was run.

Slavery was a side issue but, only a side issue. The real issue was that the south wanted to do things their own way, including slavery, including the rights to secede. Some states in the north didn't care and in fact supported slavery. "Slavery" became the issue that was used, especially once it became a 'hot new topic". As the Civil War in fact ended slavery, many Americans think abolition was the goal but, the North initially went to war to hold the nation together. Abolition came after. Aug. 22, 1862, President Lincoln wrote a letter to the New York Tribune that included the following passage: “If I could save the Union without freeing any slave, I would do it; and if I could save it by freeing all the slaves, I would do it; and if I could save it by freeing some and leaving others alone, I would also do... There has been debates on WHY but no-one can nail it down and the issue spurs in many different directions. I'm just glad slavery was indeed ended either way.

the first shot of the United States Civil War was fired from here...South Carolina had succeeded from the Union because they wanted to maintain their way of life & the ability to own slaves and the Union was starting to outlaw the practice of slavery in other states and South Carolina did not agree...a standoff insued and when the Union refused to surrender shots were fired...soon though due to blockades and running low on supplies the Union had to surrender to the Confederates and never regained control of Fort Sumpter again until the south had to surrender 4 years later uniting the states again...

Civil War