For all the assurances that the US military is an army with the ultimate task to protect the Constitution and bound to democratic principles, they sure seem to view the Commander in Chief as the sole authority, even if his orders are evidently illegal or undermine the democratic system (because Congress was bypassed).
As the war is currently going, I'd have expected at least some generals or officers to refuse orders, not because they suddenly switched sides, but simply because the orders are not democratically legitimized anymore. But nothing like this seems to have happened so far.
(Not even starting with ICE...)