There seem to be several trains of thought going on in this thread simultaneously. I think a little clarification is in order.
It's very important to remember that the militia, in colonial times, was an institution that acted strictly under
state control. Many states sanctioned private militia organizations, but they were required to follow the state governments' orders; this is an important part of the original meaning of the phrase "well regulated" in the 2A. Militiamen who refused to follow the state's orders would most likely be characterized as bandits or even rebels.
The Constitution gives Congress the power to regulate the militia (Article I, Section 8) and gives the President the power to act as commander in chief of the militia (Article II, Section 2). Some states saw this as an overreach of federal power. The prefatory or militia clause of the 2A was enacted to prevent Congress or the President from using their Constitutionally-granted powers to emasculate the militia, either by ordering militamen to disarm outright, or by ordering them to store their arms in a remote armory where their guns could be confiscated.
I believe that the militia clause was intended to act in concert with the pre-existing common-law right to bear arms, in order to ensure that militiamen were able to wield personally-owned military-grade weapons and bring them to bear if the states had to act against the federal government... but
this power would be exercised by the states, NOT by self-appointed and unsanctioned groups of citizens. The founders wanted protection from an out-of-control central government; they did NOT want anarchy!
It's important to remember that the founders had just watched the central government under the Articles of Confederation collapse, and they were well aware of the chaotic history of European royalty. Their main concern was that the central government would collapse again, or worse yet, that a weak Congress would acquiesce as the President declared himself King.
BTW the concept of the "unorganized" militia is a relatively recent one. The idea is actually intended as a dodge to ensure that military-age citizens can be drafted without requiring universal peacetime military conscription. The U.S. actually once had a universal conscription program under the Militia Acts, but it was unpopular, and the states steadily dismantled it by fabricating various reasons why certain and increasingly larger and larger portions of their military-age population were exempt.
The unorganized militia is essentially a codification of this idea; it ensures that military-age citizens can be drafted in times of war, ensuring an adequate national defense, while not requiring anything from them in times of peace.