The south did have a right to secede -- a revolutionary right. But they didn't have the power to establish their revolution.
However, there is no right to state unilateral secession under U.S. law. That was made plain in the Supeme Court's ruling in the Prize Cases. That ruling, as you know, gives the president the power under acts passed in 1795 and 1807 to suppress insurrection against a state or the United States.
Walt
This assertion is perfectly characteristic of your typically muddled thinking. Rights do not exist under the law, they exist or they don't completely independently of the law, U.S. or any other. Only privileges can be established or denied under the law. An authority that recognizes a right only if the claimant to that right has the power to enforce its claim by force is called a tyranny.
You guys can mouth this mantra till your tongues fall out. It doesn't really matter. Constitutionally, neither should unilateral secession have been forbidden. But more important is the question: what purpose was served, or whose interests were served, by coercively preventing unilateral secession - any purpose which the federal government was ostensibly supposed to serve? I think not. It did serve the kind of interests that Charles Beard suggests were really behind the Federalist's constitution, which they somewhat fraudulently foisted on the country.
The main point I wanted to make concerns the lesson that was apparently universally learned from our war of secession. No one contemplating entrance into a federation appears to be willing to do so without an unambiguous guarantee of a right to unilateral withdrawel. The lack of such was a major reason (among numerous others) why the U.S. Senate refused to approve joining the League of Nations in 1919. Even the EU, socialist creation though it is, is apparently including such a provision in its proposed constitution.