Being a voluntary military, if it really got to the point of a real uprising, I doubt seriously that the military would even act against it's own people even if ordered by any president. The members of the military are the people too, and this is not a totalitarian dictatorship. The members of our military don't have to worry about being slaughtered for refusing to kill it's own citizens.
I agree Bob and that's why I said I would never rule anything out, you never know what will happen if enough people get fed up and pissed off enough.