[JohnFen]

I don't think that whether or not the US has an interest in occupation is a large factor in this risk. If the US attacked China, China would respond, guaranteed. That would lead to a full-on war. Unless the US backed down, a nuclear attack by one side or another doesn't seem unlikely enough.

[cosmicgadget]

Where is this "full-on war" taking place? You're describing an escalation to nuclear war in the most imprecise terms.