There was slavery, and the attack on Fort Sumter, and that was it. Confederate Secretary of State Robert Toombs pleaded with Jeff Davis not to attack, but Davis wouldn’t listen. Toombs is alleged to have exclaimed that an attack on Sumter would be “suicide, murder,” and would stir a “hornet’s nest” of hostility to the South. “It is unnecessary; it puts us in the wrong; it is fatal,” Toombs pleaded. He was right, but wasn’t listened to.
Not quite. I'm getting the impression from your message that you are unaware of the fact that Lincoln sent a fleet of warships to Charleston with orders to attack them.
Were you aware that Lincoln sent a fleet of warships to attack them first?
Well *that* is why they attacked Sumter. The first warship "Harriet Lane" arrived and fired on the Nashville. That is when General Beauregard decided the rest of the fleet wouldn't be far behind, and so Sumter needed to be neutralized before the other ships got there.
Very rational military decision that.
Lincoln shouldn't have sent those warships. That is what started the war.