Breaking up the USA, worse than breaking up the EU :)
Because we allow free mobility across state lines, the “Balkan-ization” of the USA is happening daily as people pick up and move to a state that fits their sensibilities.
At some point, the blue states will become deep, deep blue and hopeless. Then, the new borders will become obvious.
Also part of this “let it happen on purpose” (LIHOP) plan is to allow states to fragment into smaller states, such as California and New York.
People are voting with their feet. I do not think there will be a hot CWII.