I don’t think that anyone here said that no one could secede - just that they way the slavers tried to do it wasn’t jake.
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Interesting thought.
What — in your view — would have made their attempt at secession “jake?”
Had they sought mutuality within their brother states.
Controversies between the states, or between the states and the federal government are to be resolved with the supreme court as original jurisdiction, per Article 3 of the Constitution.
The slave states did not write up their grievances, file a court case seeking legal resolution, as would be constitutional, nor did they introduce a bill into congress, nor did they try to have the congress submit an amendment to the constitution. Any of those approaches would have been legal. They tried none of them.