There are a number of reasons there might be a civil war breaking out in the CSA itself the most likely being that states themselves can tax imports from other states. I think that would happen in Louisiana and Mississippi at least. They would tax everything coming down the Mississippi and that would be resented by Arkansaw and Tennesee. Some of the border states might eventually want to become Free States and find that is impossible under the CSA Constitution. A state might storm off because they don't like whoever got elected CSA president. After all that is what formed the CSA in the first place. Any other reasons for a CSA Civil War and what would be the sides and what would it look like?