I've had a few second amendment disagreements in my short tenure as a gun owner. Some aspects of a "well organized militia" have changed in appearance over the years. Though that statement was just the preamble for the main statement of the right to bear arms shall not be infringed. But in fairness, instead if having Indian battles on the frontier and defense from England, we now have drug thugs, gang bangers and radical islamists. Depending on where you live, that can make present circumstanes more scary than past circumstances! And the most important reason that the founding fathers wanted firearms in the hands of the people......as a defense against a tyrannical government. In Colonial New England, the British marched to Concord to keep the colonists from getting gunpowder. In Colonial Williamsburg, the British troops first took over the city's powder magazine. In 1933 Nazi Germany banned guns.....the rest is history. In the late 1960's, when the "Deacons For Defense" gained the right to bear arms, it wasn't so easy anymore for those KKK thugs to just go in and shoot people they didn't like.
It wasn't so much the fear of Great Britain coming to get us back then, as much as it was a safeguard against the United States adopting the monachial and imperialistic aspects of an oppressive and tyrannical government.