Where have you been? There's been groups pepping for a second civil war (the meme-name is "boogaloo", as in "Civil War 2: Electric Boogaloo") for at least a decade now.

I'm optimistic that red and blue America will have something more like Czechoslovakia's Velvet Divorce involving minimal bloodshed, but I'd be surprised if the USA makes it to 2100 as a single polity.