Anonymous
One thing that has to be considered about the military is that they have families. If the military take side with the government and put the boot down hard on the people I think they will have to worry about what happens to their relatives.
Numbers are not on their side either. They can count on about 2M people to control a huge country and 300M people. And those 2M include 800,000 reservists all reporting for duties (optimistic for the reason above) and all the ones currently abroad or at sea. Add that a good number of personnel are no more than paper pushers and that they would need a good number of people just to secure their facilities, other government facilities, and strategic installations (refineries, power plants, transportation, …) that leaves not much to keep the people in check.
Sure the government can count on all the DHS people but even there, TSA is useless and for the rest the considerations above needs to apply.
I still go for a split military/paramilitary in case of collapse. Now I need to figure out what Russians, Chinese and the rest of the world in general would do about our nukes.