Oh stop it. Please. The USA needs to split up peacefully and the Chinese aren’t going to invade. But even if your crazy hypothetical were true then if we stay united the entire country becomes a fascist state just like China.
It's possible there's another outcome that's more likely and less bloody than what would follow from a civil war of forced unification. I suspect there are better arguments for your "separatist" point of view than you're making.
But you keep trying to swat away the first thought that any strategic-minded visitor from another country or from Mars (to take an example) would have, which is that territories that are split tend to be way, way more vulnerable. (Hence the expression, which I believe is from Caesar: "Divide and conquer.")
Maybe there's an argument to be made that this isn't a textbook case--that, because of the nature of the territory, going independent might actually empower the conservatives who occupy most of the land in the West. If there's time for it to take place, an internal realignment might occur. I happen to think it's dicey, but you could make that argument. And there's always: A country in the middle of a civil war can be vulnerable, too. Go ahead. Whaddya got? I'm just being Captain Obvious. But for the sake of a million or so casualties, I'd love to be wrong.