“Our form of democracy rests upon the citizen’s participation … especially including participation in the armed forces. That was the great principle of the French Revolution: the nation in arms, meaning the people in arms as distinct from a professional standing army. The nation in arms was considered the safeguard of the Republic, the guarantor against tyranny and military coups d’etat.
The same idea underlies the fundamental principle of the right to bear arms as guaranteed by the U.S. Bill of Rights for the special purpose of maintaining a ‘well regulated Militia’ to protect the ‘security of a free State’ … To serve under arms in this sense is not only a right but a criterion of citizenship”
from Barbara Tuchman: ‘Practising History’