The funny part is it wouldn’t take “troops” to cause major disruptions/failure here.
A couple of dozen men in each ‘grid’ zone, each armed with a .22 rifle and a non-descript car could do more damage and cause more havoc than a larger group of ‘troops’. With our fragile power infrastructure, it wouldn’t take long nor that much effort.
I won’t say how, but anyone with half an imagination can figure it out.
They don’t need to hold ground, just ‘stop’ us.
No power, we’re effectively stopped.
Suddenly the military has other things to worry about than some sandbox somewhere, they have Chicago/Detroit to deal with.
Here’s a few thoughts to ponder
There is no need to “hold” anything.
Just wait until the shooting ends and deal with the survivors.
Chances are, they’ll be very happy for rescuers to arrive.