Our Framers knew that sovereignty had always followed the sword.
Our English heritage and experience under James I, Charles I, Cromwell, and the military occupation of Boston by George III all solidified a fear of professional soldiery.
OTOH, militias were not to be feared if strictly composed of freeholders, and were regularly exercised, disciplined and kept well-equipped.
Among the things I admire about the Framing generation was their ability to learn from experience. Our Revolutionary War was a long, drawn out affair due in part to general reliance on militia forces. Republican Rome was the model and George Washington was our Cincinnatus, who lead an army of freemen against professional soldiers. Most of the time, our militia army lost battles.
Look at Article VI of the Conferation: . . . but every State shall always keep up a well-regulated and disciplined militia, sufficiently armed and accoutered, and shall provide and constantly have ready for use, in public stores, a due number of field pieces and tents, and a proper quantity of arms, ammunition and camp equipage.
As per the Preamble to our Constitution, providing for the common defense was one of the purposes of the American Republic. Having learned from experience, our Constitution provides for both republican militias and professional armies.
A gaggle of young men with weapons but without training, discipline, equipment isn't a militia; it is a mob.
Taken all together, that is why the 2A is so carefully worded. Well drilled, i.e. regulated militias were expected to defend the greater republic. Since militias are so necessary, arms may not be denied to the people.
Among the irritating habits of the Left is their shallow, ignorant dismissal of most constitutional provisions as nothing more than the expressions of oppressive white men.
There is a rich history behind every clause in the Constitution. It is our duty to discern them.
References:
The Stuart Age, by Barry Coward, 1980.
An Argument Shewing, that a Standing Army is inconsistent with a Free Government, and absolutely destructive to the Constitution of the English Monarchy, by John Trenchard and Robert Moyle, 1697.
A Letter Balancing the Necessity of Keeping a Land Force in Time of Peace by John Somers, 1698.
A Short History of Standing Armies in England, by John Trenchard, 1698.
Discourses on Livy, by Niccolo' Machiavelli, 1513.
Thanks for the insight.