[rtkwe]

The US could cut back and still compete in the West Pacific/South China see but it would have to focus there very heavily to the detriment of the existing implied obligations to NATO. Part of the US's politically dominant position post WW2 is that we've signed ourselves up to be anywhere in the world fighting a large scale conflict inside of a month with huge stockpiles of everything you need to fight all over the world, including one floating one that can backup the standard land based prepositioned stocks. [0] Granted a lot of that was also enabled by being the only major economy not significantly bombed through the war but that advantage was heavily invested in since then.

[0] Wendover Productions has a great video about the insane amount of logistics dedicated to the goal of never having to wait for materiel practically anywhere in the world. https://www.youtube.com/watch?v=iIpPuJ_r8Xg

[mrguyorama]

Coincidentally, this whole Russia Ukraine war has pushed most NATO nations to build up their military and re-arm. If Europe can actually defend itself, the US's obligation there reduces significantly.

[rtkwe]

Yeah and it's much cheaper to operate locally and defensively than it is to have a very expeditionary and overseas force the US has so they /could/ close the capability gap for less money. There is a bit of difficulty having so many different militaries needing to work together but it's something that works with practice.