A militia is a local self-oragizing armed force. One that is well-regulated has rules. The national guards of the various states started as militias as there was no standing national army, by design.

This is why when we read about the Civil War, we read things like the "4th Wisconsin Volunteer Infantry Regiment". It was constituted, organized, recruited and regulated within the laws of the state.

Before the individual states began regularizing militias, each community had their own, like at Lexington and Concord, for example. The Minutemen were militias that self-organized in each community. They determined whether or not they would heed the colonial authority. The colonial governor could not issue them orders. He could ask them to do things.

The constitution is silent on what constitutes a "militia". I think you and I could organize one and establish by-laws that members must follow and that would be well-regulated. This is why the fed gov has been so reluctant to address what some people believe to be a problem with militias -- they are constitutionally protected.

So if we use the second part of the amendment to justify negating the first, we empower the private militia movement. Which is the greater threat to the national government, individuals acting individually on their gun rights or a multitude of private militias acting on their constitutional rights?