Trump is an idiot, it’s the faction behind him who really decides. He is a narcissist readily manipulated. The main thing are the resources which you identified. The US munitions are now coming mainly from strategic reserves because China sanctioned the US off magnesium, tungsten, antimony and other essential purified ores. The distant second in resource extraction and purification is Russia.

The US is over a barrel in resource options to feed its war industry with the only backup being an aging, difficult to maintain nuclear arsenal. That’s why both acquiring Greenland and Canada as well as an attempted alliance with Russia is important. That’s also why Trump, a week ago, invoked wartime powers, never used since WWII, under the Defense Production Act to bolster U.S. production of critical minerals to restart U.S. production.

The US is retrenching into America, as in North, South and Central. To that end, they’re thinking ‘fortress America’ where they completely dominate ‘their region’ and create as much chaos elsewhere until they’re ready to reconquer. Using nuclear weapons on the rest of the world may be part of it, if they can be reasonably sure that 'their' region won't be retaliated against. The US has used nuclear weapons on civilians many times including Hiroshima, Nagasaki, depleted uranium everywhere, possibly tactical nuke on Beirut port, possibly also in Tartus and who knows where else and this will probably escalate as their depraved savagery has no bounds. Only when this truly evil empire of the ‘West’ that has been ravaging and torturing humanity for over 400 years is completely checked will their depravity stop, and China is going about stopping this beast the smart way. However, this beast will have at least millions more victims before it hopefully dies forever.