The Divided States of America

So many states are divided within. Colorado is red in the north, south, (mostly), east and west, with a wide blue streak vertically on the map, down the middle. Illinois has bright blue Chicago, and, I believe red all around the rest of the state. Wishigan (Northern Michigan) is red I think, or at least has interests different from those of Detroit. Oregon and California are both redder, the farther from the coast you go. 

I realize those statements are only mostly true, but the point is how do you split up the country with pockets of resistance in the big cities, or if you are a lefty, resistance outside the big cities? Do you become totalitarian, and force people out of your states? Do you set up some sort of transfer portal, where people can trade properties? That might work if the split is declared, but doesn't go into effect for a year or so. But, trading properties won't be easily accomplished, in large part because most lefties live in urban areas and most righties don't want to live that way. 

I don't know what the answer is, but I'm sure the divorce would have to have borders that split apart existing states in some ways.

EDIT: I suppose the people who remain in a state that is dominated by the opposite ideology, would be controlled simply by being so outnumbered that they couldn't stop the federal institutions in their new country, from passing laws which they oppose, but are too heavily outnumbered to stop.

But state and local laws is a different story.