The military would not have "stepped in" under its own accord. It may have been called in (probably in the form of the state national guards).
If so many former military officers are positioning themselves so well in industry to effect this coup, maybe they could also step in and restore a larger portion of US manufacturing and sidestep the issue of your last paragraph. It would certainly be easier than destroying a country.
Judging from 4chan, twitter, gab, I think currently its the "stolen election" Trump supporters. But it might be a growing coalition of those that oppose "communism" as they see it. Progressive policies, reparations, and so on. The disgruntled right. Which is actually a lot of red states...most of geographic land area of the US.
However, I remember when the US early in the pandemic ran out of masks, since the masks were manufactured in China and was telling its people masks were not necessary, to preserve supplies for healthcare workers. Recently the chip shortages are causing car manufacturing to grind to a halt.
Is the US military anything without industry? Seems to me like almost under all scenarios, US military success, is heavily based on US industry's ability to supply its weapons and logistical needs. With politicians behind outsourcing so much to China, can the US even sustain any direct conflict. Seems to me, that diminishing industrial capability has to be a giant sore point for the military. Especially when there are money trails of some politicians accepting money from China.