At the always interesting blog "The Volokh Conspiracy", David Kopel has dug up a 1942 decree by Maryland governor Herbert O’Conor calling on armed citizens to serve in a reserve militia to defend the state against Axis "parachute troops, saboteurs, or organized raiding parties" or the actions of "enemy sympathizers within our State". It's notable for its plain statement that volunteers would be expected to provide their own weapons and would be expected to have basic competence with them -- even at this relatively recent date when the standing army was well-established as a tool of American imperialism and the foundations of the military-industrial complex had been laid.
This is what the "well-regulated militia" in Amendment II means -- a citizen body familiar with the use of arms is necessary for the security of the nation. ("Well-regulated" here does not have the meaning of "subject to extenisve regulatory law" but rather "effective and precise" -- in the same way that a mechanical timepiece is "regulated". In order to have people familiar with arms, it is necessary for the people to have them. Therefore, the Second Amendment tells us, the new nation shall not interfere with the vitally important -- not just for individual liberty but for the security of the nation -- natural right of the people to arm themselves.
The purpose of the militia as seen by the founders was not merely to supplement the army, it was " [t]o render an army unnecessary", to be the "substitute...for a standing army, and the best possible security against it," as Hamiliton wrote in Federalist paper 92.
That's right: the standing army, service in which is so often touted as a patriot virtue, is not even supposed to exist under the Founder's plan; instead we should have every good citizen armed. There's a cure for the military-industrial complex and foreign imperialism you won't find either Democrats or Republicans pushing these days: abolish the army.
The Maryland Minute Men of 1942: Armed citizens summoned to homeland defense (Washington Post)
The mission of the Maryland Minute Men is to furnish immediately, local protection against parachute troops, saboteurs, or organized raiding parties. It is planned that the units be confined to their own communities so that there will be assurance at all times that every residential section of Maryland will have protection.
No prescribed complete uniform will be required. Distinctive arm bands and caps or other items may be furnished by the State, the County, or by the men themselves. For the present the hard-pressed Ordinance Department of the United States Army cannot be expected to furnish sufficient arms, ammunition, or equipment. Hence, the volunteers, for the most part, will be expected to furnish their own weapons. For this reason, gunners (of whom there are 60, 000 licensed in Maryland), members of Rod and Gun Clubs, of Trap Shooting and similar organizations, will be expected to constitute a part of this new military organization.
Officers will be drawn from the immediate area in which they are to serve. As Army officers have pointed out to me, the familiarity of the members with their particular locality, with the terrain and road not in the respective communities, will be of great value in resisting any hostile efforts against residential areas and important public necessities.
No intensive training program will be adopted. While sufficient preparatory work must be undertaken by the Minute Men, care will be taken to avoid unnecessary demands upon their time. No guard duty is to be included as a regular part of the program for the new force.