A sawed off shotgun loaded with buckshot is a VERY GOOD deterrent to an attack by any armed person.
I don't know whether the Army issues them or not, but I am pretty sure that there are at least a few in the hands of troops in Iraq, Afghanistan and perhaps elsewhere.
The whole idea that there is a "well-regulated militia" consisting of men (and perhaps women, there has been no ruling on that) who are totally unaware that they are a part of an "organized militia". is a joke.
Militias were common in Missouri until the time of the Civil War. I don't know how well men were trained, but there was a standing militia. When the Civil War started, the local yokels attempted to take possession of the weapons stored in the militia's forts, and in some cases succeeded. The elected governor of MO proclaimed the secession of MO from the Union, but the commandant of the garrison in St Louis took Jefferson City and proclaimed the secession as never having happened. MO had an exile government in Texas until the defeat of the CSA.
After the Civil War, the militias were not reconstituted, because there was a lot of animosity on both sides. Similar events occurred in other states.