"With this situation in mind, the Founders wrote the Second Amendment, which says that, 'A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.'"
The key word here is "Militia."
At the time the Bill of Rights was written, America had no real professional army, and what military it did have was in the form of 13 separate state militias.
The Founders saw these militias as the best check against the rise of the standing army, and so they wrote the Second Amendment to make sure that they were always protected. But that's only part of the story.
And after the Constitution was written, southern slave-owners, led by Patrick Henry (Virginia's biggest slave owner) started freaking out that their slaves could be constitutionally freed and then drafted by the federal government, which was given the power under Article 1, Section 8 to raise a national militia.
The slave-owners worried that this national militia would eventually be used by Northern anti-slavery types to destroy the slave patrols and maybe even the institution of slavery itself. So what did those slave-owners do?
These protections aren't obvious, but they're there, and we know this because of the difference between James Madison's original draft of the Second Amendment and the final version included in the Bill of Rights. Madison's original version of the Second Amendment reads as follows:
"The right of the people to keep and bear arms shall not be infringed; a well armed, and well regulated militia being the best security of a free country: but no person religiously scrupulous of bearing arms, shall be compelled to render military service in person."
This version of the Second Amendment didn't fit well with slave-owners because it included words like "country," words they felt could be used to justify the creation of a national militia that would include freed slaves -- a backdoor way for a Northern president to free Southern slaves. And so Patrick Henry lobbied James Madison to rewrite the Second Amendment into the version we know today.
He spoke passionately at the Virginia Ratifying Convention:
"If the country be invaded, a state may go to war," Henry said, "but cannot suppress [slave] insurrections [under this new Constitution]. If there should happen an insurrection of slaves, the country cannot be said to be invaded. They cannot, therefore, suppress it without the interposition of Congress ... Congress, and Congress only [under this new Constitution], can call forth the militia."- Advertisement -
"In this state [of Virginia], there are two hundred and thirty-six thousand blacks, and there are many in several other states. But there are few or none in the Northern States ... May Congress not say, that every black man must fight? Did we not see a little of this last war? We were not so hard pushed as to make emancipation general; but acts of Assembly passed that every slave who would go to the army should be free."
As Michael R. Burch wrote, "Henry was obviously convinced that the power granted the federal government in the new Constitution could be used to strip the slave states of their slave control militias. He anticipated exactly what Abraham Lincoln would end up doing: