America wanted isolationism (and got isolationism) thinking they would keep their global standing and economy (that makes their military strength possible)... mostly to spite a strawman conception sold to them by theocratic extremists who want them isolated for much the same reason an insane and insecure bf wants to keep /his/ hoe isolated, to be able to exert his will and ensure she ain't watching the bbc. In keeping with that metaphor, america is a bf whose been dumped, but too d(jt)umb to realize or accept that they've been dumped.
And the political opposition: middle-management pta moms.
Best case scenario, america becomes brittian, nominally free and fairly culturally relevant/prosperous, worst case, giant nk, likely case, mostly impoverished russia with a few affluent-esque cities... and where the oligarchs falling out of favor with the regime is something akin to falling out a window. lul, american patents were /enforceable/ internationally because of americas' (former) power #cheers
of course, american consumption is unsustainable and eventually a lif-style decline would occur, despite gravity being a hoax-science it is a real
https://en.wikipedia.org/wiki/Population_growth#/media/File:Absolute_increase_in_global_population_per_year,_OWID.svg
https://www.youtube.com/watch?v=9_TM-kziubM&t=1s