The US can’t engage in a major war without losing the homeland at this point. You can take that to the bank. This isn’t just about being a paper tiger stretched thin, but no borders and divided nation means the civil conflict will surge the moment the wrong move is made.
The instruments of foreign states were emboldened instead of being removed. The cheapest war is having your enemy wage war on itself. Mostly by indirect means like fent/US Opium War, or by empowering a generation to overthrow the others. However the direct conflict can be waged by withholding trade without much need to sink carrier fleets.
Going to have to gnaw off a limb or two just to get out of the trap at this point.