And what exactly is "the Militia?" as understood by our Founding Fathers?

And now for a bit of Historical Analysis by the SUBCOMMITTEE ON THE CONSTITUTION
of the UNITED STATES SENATE NINETY-SEVENTH CONGRESS, Second Session, February 1982:

In the Militia Act of 1792, the second Congress defined "militia of the United States" to include almost every free adult male in the United States. These persons were obligated by law to possess a firearm and a minimum supply of ammunition and military equipment. This statute, incidentally, remained in effect into the early years of the present century as a legal requirement of gun ownership for most of the population of the United States. There can by little doubt from this that when the Congress and the people spoke of a "militia", they had reference to the traditional concept of the entire populace capable of bearing arms, and not to any formal group such as what is today called the National Guard. The purpose was to create an armed citizenry, which the political theorists at the time considered essential to ward off tyranny. From this militia, appropriate measures might create a "well regulated militia" of individuals trained in their duties and responsibilities as citizens and owners of firearms.

If gun laws in fact worked, the sponsors of this type of legislation should have no difficulty drawing upon long lists of examples of crime rates reduced by such legislation. That they cannot do so after a century and a half of trying — that they must sweep under the rug the southern attempts at gun control in the 1870-1910 period, the northeastern attempts in the 1920-1939 period, the attempts at both Federal and State levels in 1965-1976 — establishes the repeated, complete and inevitable failure of gun laws to control serious crime.