MOYERS ON THE NATIONAL RIFLE ASSOCIATION

This clip is from a previous mass killing, or the one before that (there are so many; too many) but Moyers' comments still apply.

 "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."

Yes, that's the Second Amendment.  The right to form militias for the common defense is the key here. This has been argued till people are blue in the face, but it really wasn't until the Gun Control Act of 1968, and the Hatch Commission, that it became popularized as the individual, personal right to carry a gun around. What became known as the "individual rights" argument was promoted and pushed by the conservative movement and spearheaded by the NRA, and this decade its clear a conservative judiciary takes these arguments seriously. Regardless of interpretation, all would agree that when the words were written two centuries ago there weren't any automatic assault rifles. Needless to say, these rights are not immutable--they are the word of God, after all, but man--and are intended to serve us but can be looked at over historical time if need be.

Here is a valuable footnote. In 2008, an amicus was submitted to the US Supreme Court and signed by 15 eminent professors of early American history, and it concluded:

 "Historians are often asked what the Founders would think about various aspects of contemporary life. Such questions can be tricky to answer. But as historians of the Revolutionary era we are confident at least of this: that the authors of the Second Amendment would be flabbergasted to learn that in endorsing the republican principle of a well-regulated militia, they were also precluding restrictions on such potentially dangerous property as firearms, which governments had always regulated when there was 'real danger of public injury from individuals.'”