Kind of already happened last round. There’s reports Mark Milley staged somewhat of a soft coup with the joint chiefs, and then they withheld troop numbers from him when he ordered a withdrawal from Afghanistan.
At this point I'd wager a US military leadership coup + 4 years of marshal law would result in better governance than anyone in the Republican party leading. After 4 more years of an unrestricted Trump, not so sure.
If successful, they're going to purge the military of non loyalists who believe the constitution is more than a doormat. The goal is to violate posse comitatus it seems.
Yeah, it's not going to work that way. The Joint Chiefs are already holding meetings on how to handle illegal orders from Trump, and those would go out the window.
Facists always pick people for loyalty first and competence a distant second. This is ultimately self-defeating, but they can do a lot of damage before things take their course.