I'm gonna just go ahead and disagree a little here.
Not long ago, I read an interview with a respected, retired military analyst (can't remember the source, but it wasn't in some obscure, non-credible right-wing site), anyway, the guy's position was that military authority -- in terms of potential martial law -- was an illusion.
One point made:. The military research study done a few years back that projected conservatively, approximately 47% of active military units would likely not only refuse orders for action against citizens, but over 80% of those would most likely actively resist/defend against these types of actions. (Research among law enforcement personnel (not administrators or chiefs of police) reflects a higher percentage of over 65%.
Hundreds of times more small arms in the hands of the citizens than the military, and the military doesn't have near enough for small arms for 10% of its forces.
Oh, and the President has to ask the states to nationalize their national guard troops.
The government clearly has reason to be fearful of the populace which easily explains the continuing push to disarm the law-abiding citizens.
Oh, like we attained control, with all our resources, of the population of Afghanistan in 25 years? I've seen, over the years, credible estimates that the federal government might be able to gain "control" over only a handful of cities but probably couldn't maintain that control for long.