I think he has already explored that option, but if he tried to enact it, all hell would let loose and would result in massive internal upheaval of the violent kind. As ever, he says something and waits for the reaction before pursuing whatever he is trying to implement. The military swears an oath of allegiance to the Constitution, not Trump, so you have an instant division of the armed forces, and as much as he thinks he is popular, that would be a step too far in the view of most Americans, whatever side they are on. Only him and his buddies would benefit in the short term at the expense of the rest of the population who will of necessity have a hard time. But in time he will turn on his friends too, as all dictators end up doing this eventually when someone disagrees with them.
IMO It won't fly - thankfully.