I can see something more like a revolutionary war then civil war. The remedy will be the splitting of the US into 3-4 independent countries(composed of states). These units will back out of all US debt obligations and ‘start over’. Almost like the breakup of AT&T many years ago. Each unit will have their own constitution and foreign relations departments.
I assume, of course, that you are excluding CA, NM, AZ, and most of TX from consideration. The invasion from Mexico has already settled the future for these states.