China is too risky a military target.
If Trump wants a short victorious war, then Syria or Iran are way easier.
Except nobody cares about Syria or Iran in the US, nor are they considered serious threats ordinary Americans might worry about.
Besides, Trump has already got the Jewish conservative vote locked thanks for his stance on Israel, so there isn’t much electrical boost he can expect from attacking Iran.
Squaring up to China is less about winning and more about invoking a major threat and telling Americans Trump is the only man who can protect them from this terrible yellow peril.
In that respects, even a military loss for the US might not be a total disaster for Trump, as he can blame Obama for him having inherited a bonked military and say only he can rebuild American military dominance.
But the most likely military scenario would be that Trump have the USAF and/or USN fire a handful of cruise missiles at max range at China’s SCS islands and run for home immediately, that causes minimal damage (so look to his Syrian strikes as a benchmark). At the same time he pulls all US assets out of the Eastern Pacific to deny China any easily accessible and proportionate retaliatory targets.
China will make the expected diplomatic noises but issue an ultimate to SK, Japan, maybe even Australia since they are near the top of China’s shit list right now - close down all US military bases on your soil within a set amount of time and evict all US military, or China will retaliate by striking at those bases on their soil.
If they kick the Americans out, great. If not, I think China will ostensibly strike at American bases on their soil, but in doing so will probably deal a heavy blow to their local military as well since when the PLA launch their ‘retaliatory counter strike’, they are going to kill anything military in the way irrespective of whether they look like they might try to interfere.
In doing so, China will not only have driven America out of the western Pacific, but also dealt its regional security assurances a deathblow. As who would take American assurances seriously if they poked the hornets nest and skipped town to let their local allies take the heat for that?
