Total martial law is not possible in all of America. Let’s look at the facts:
The US Army, using the study of counterinsurgencies and military tacticians, have generally figured that at a bare minimum, 20 counter insurgents are needed per 1000 population. Let us consider that if there was attempted martial law, the situation may get violent enough to resemble an insurgency (look at Los Angeles in ’65 and ’92, for instance).
This rounds out to about 2% of a population, at a minimum.
Now, let us do some math:
Active Duty US Armed Forces (1.3 million in all branches)
Population of the US (Around 310 million)
1.3/310=.0042=Less than 1%
But, OK, let us include all reservists as well, on top of all police forces (about 1 million cops in America).
2.1 million + 1 million/310=.01.
1 percent, and this is considering that the military has relatively few infantry men. I doubt a Boatswain’s Mate in the Navy would be able to help much with a martial law situation. So even by this metric, the US military would fall short by it’s own standards to impose martial law on all of America. As for other NATO militaries–they have their own problems, not to mention NATO is not just some monolith either. Even if you add in 2 million other NATO troops, you would still fall slightly short of the bare minimum of 2%.
Overall, I think all this fear of Martial law is unjustified. For sure the US military could enforce martial law on a single *region*, but not across all of America. If it tried, it would fail. God knows we weren’t doing that great in Iraq, for instance. And in that case, American troops weren’t asked to shoot their own, either.