Long term possibility (aka 'the bad ending') is that the fash project comes to full fruition and the US is able to circle the wagons in the north and stay alive another 50 years before the full biosphere collapse.
Short term possibility (but not a 'good ending') is that a black swan event happens, like a nuclear exchange or a devastating disaster like the clathrate gun going off, and supply chains are disrupted so heavily and so fast that the federal government can't maintain power. This I could see happening ten years from now.
