Thought provoking as always Andrew. Thank you. It is quite likely US will "break up" but present itself as still a "coherent whole" for a time being, while the population segregates voluntarily along the lines you suggest. It will still try to maintain a federal war-machine as long as oil supplies allow, but once oil get too scarce for the Pentagon to project power globally, the true break-up will set in. Although we can have nuclear aircraft carriers, fighter jets will not run on solar panels.
The world is in the process of dividing up the remaining fossil fuel resources and Europe is in sad, sad shape. Like I said in the article below "the colonizers are about to get colonized".