Texas vs White ruled that a state cannot sucede from the Union. At one time a state could prior to the civil war.Why doesn't Texas secede from the US?
It was originally the intent of the constitution that if the government becomes oppressive that a state could declare its sovereignty.
Subtracting the British and the Bank of England’s initial use of the colonies as a means of slavery for exports, namely cotton, the south was just in succeeding from the Union.
The mistake was P.T. Beauregard firing on Fort Sumpter. Had the south not fired in a federal position things would have been different.