So is Cascadia.

A key to successfully "breaking up" into regional polities would be figuring out how to ensure that people who find themselves in the "wrong" polity in terms of their own political/cultural orientation have a workable way to relocate without there being insurmountable cost barriers. Not an easy problem...but perhaps solvable.

Lots more challenges (equitably dividing things like national debt, the US military, etc.), but I've feared for some time now that the alternatives are far worse.