The Southern view was all about State's Rights, but the only right they cared about was the right to own slaves.
I agree with that in this sense: the South's economic power was entirely wrapped up in free labor. Lose that, they reasoned, and they lost their economic edge. The roughly 1 in 5 Southerners who owned slaves doubtless found plenty of useful idiots, like my ancestor, who may have been sympathetic to a call to defend his state's sovereignty that they could use to preserve their economic power.
I am truly sorry for bringing to mind painful things for you. Clearly Adam's motivation for enlisting had nothing to do with democracy or Christianity. But neither did Pat Tillman's. There are, no doubt, true believers in our military that are there fighting for motivations that don't have anything to do with the reasons the elite want the war fought. In other words, ascribing to all of them a single motivation for fighting - let alone the powerful's reasons - is overly simplistic. That's the point I was trying to make when I said that claiming the war was fought over slavery was overly simplistic.
[Edit: tpyo]