General Discussion

I retired from the AF after 28 years of active duty service. The question of what is an illegal order is something we faced. In most cases, the person giving the illegal order was informed by the person(s) given the order why it was illegal and the person giving the order backed down when they had the correct information. If the person giving the illegal order didn't back down it was elevated up the chain-of-command where it was squashed and the person giving the order had to explain themself to their immediate supervisor or commander.

As for DonOld Trump giving the military orders to go into the streets and round-up illegal immigrants I believe the Chiefs of Staffs for the military branches will try to push back on the order saying it violates Posse Comitatus which is using the military for law enforcement. Posse Comitatus does allow use of military resources to support law enforcement such as providing troops in a support capacity at the border or for drug interdiction. Although the Chiefs of Staff may resist the orders I have no doubt DonOld Trump would replace any one of them if they refused to follow his orders. Going down the chain-of-command, many officers would resist as best they could the orders and if they refused they'd too be replaced. Unfortunately, there are enough officers and enlisted who would have no problem doing whatever DonOld Trump wanted them to do. I wouldn't put it past him to require military officers to sign a loyalty oath to him.

So, as far as a military revolt, no, there wouldn't be one but IMO, it would not only tear the military apart but it would severely damage it for years making the U.S. weaker militarily. In addition, the services are having a hard time meeting their recruitment quotas and this would further negatively impact recruiting. If that happens, then look to having the Draft, which I oppose, return.