If states like Virginia, the Carolinas and Georgia could have known in the 1780s what would happen to them 80+ years later, they never would have ratified the Constitution in the first place. That right there is enough to convince me that they had every right to secede from the U.S.
Slavery had been abolished in the North by 1804. Slavery was vital to the Souths economy and it choose a path of violent secession and lost.