Officer's oath swears to protect and defend the Constitution, no mention of the president.

Enlisted oath adds they will obey the orders of the president.

So a president or his intermediary just needs to find the right Master Sergeant. In theory.

But not to worry, there are plenty of authoritarian-friendly colonels available. Their oath doesn't prohibit them from following a president's orders.

Wrinkle: all officers and enlisted are required to refuse illegal orders. But if you do so, you better be right.

Of course, in this new United States that the Supreme Court created this week, summary executions could become a motivational tool.

https://en.m.wikipedia.org/w/index.php?title=United_States_A...

https://en.m.wikipedia.org/wiki/United_States_Uniformed_Serv...

https://www.acslaw.org/expertforum/what-the-law-of-military-...

https://en.m.wikipedia.org/wiki/Summary_execution