President Orders Gun Confiscation...Niow What?

Let's review the current thought process. We will assume that President Smith (Biden, Trump, Nixon, Hayes, whoever) has found a legal way to make a federal gun confiscation confirmed as law and the order has been issued to the military to enforce it. In this hypothetical scenario posse comitatus has been suspended and so far, everything is done properly and legally.

If the commanders of the highest order receive such a command and believe it to be unlawful, they will request a legal review. If that legal review passes and they are still not pleased with the results they can file a federal lawsuit through their branches which could be used to test it for constitutionality.

The military not only has the right but the duty to defend the constitution above the president. They do not get to decide what is constitutional. That is for the courts. If the courts come back and say it is constitutional, then the military would have to comply. If they do not, then that could result in removal from their position and can go so far as criminal charges against the commander.

Really any commander can execute the process of legal review if they believe they have received an unlawful order. It is fair to say the risk of the negative repercussions for failing to obey gets higher as they get further down the ranks, but that may be because of inexperience in challenging orders believed to be unlawful.

Perhaps a company or battalion level commander or a JAG officer could weigh in.

The idea that the military would “turn on him" is simply naive and unrealistic. That is called a coup and is not how the military works.

More likely several lawsuits from the people would be filed, delaying the action for a long time, the gun-rights lobby would be financed, and the votes would put a republican supermajority in power. Then the law would be repealed and that could spur the legislature on to have a constitutional convention and end this debate once and for all.