More on the Second Amendment: Glenn Reynolds notes this book by Robert H. Churchill, which looks militias from a libertarian point of view and asks how today's militia movement got labeled "extremest" considering the origins of our own revolution.
I think the "extremest" label with respect to the 90's militia movement is more accurate, as they were often barely organized cover for wanna-bes, racists, Nazis, and conspiracy groupies - not proper militias nor groups who were very interested in protecting a free State.
Prior to the creation of the National Guard, private militias were common in the US. One of my old National Guard units, the 1/141 FA - the Washington Artillery - started out as a private militia in New Orleans before the Civil War. (With privately owned cannons, no less!) Membership was by invite only then, and to be in the Washington Artillery was considered a plum in New Orleans high society.
To me, this is where the first clause of the Second Amendment - "A well regulated Militia, being necessary to the security of a free State..." comes into play. Let private militias exist, and regulate them with respect to the security of a free State - not the security of The State.