>>123002In earnest?
It was about slavery. 60% of the South's GDP was dependent on it. Labor is almost always the largest factor in GDP.
However it was an overreach of Federal power. I think Lincoln even knew that and was reluctant to take that step himself. That overreach set the precedent for the empire we became; that the founders never wanted us to be. Our state governments used to matter. Now they're mostly trivial. Washington more or less presumes to rule for all. Even now Marijuana is still illegal in Colorado et al. The feds are simply benevolently choosing not to enforce it.
The south is a technological backwater blight because the north "punished" the south after winning. Lincoln wrote extensively how you absolutely must not do that. But President Johnson did anyway. Stripped of its capital and wealth, property values fell and aid was never sent. Resentment grew and racism became more entrenched than ever.
Britain had slavery. But they don't have a nigger problem. No ghettos for blacks. Ever wonder why we do? (They do of course have a muslim problem, as they self-segregate into their own ghettos and resist assimilation).
With the exception of Texas, the southern states never really recovered. They almost all lag behind in development compared to their northern counterparts. Mississippi consistently ranks worst by every measure.
By most analysis, the South never stood a chance of winning. They simply didn't have the economic or foreign support.