The Second Amendment is pretty unique in the fact that it is the only Amendment with a preamble.
Why not just simply say:
"The right of the people to keep and bear arms shall not be infringed."
Why did the Founders decide to qualify the people's right?
In essence, Laurence Tribe bases his pro gun control argument on the meaning of that preamble, saying that the people's right to keep and bear arms exists only as those rights apply to an actual State's militia; a "well regulated" State's militia.
Tribe's argument is that the Amendment applied to the State, and that it meant that the State was able to limit possession of arms to an actual State's militia, there to protect itself against the Federal government.
That's the Amendment read from the left.
I read it from the right, and from the right it says that the people's right to protect itself against anything that would destroy our Constitutional Republican form of government, is essential to the continued survival of our Constitutional Republic, and that as such, our right as individuals to bear and keep arms must not be infringed.
So, in a nutshell, the government is not constitutionally limited from requiring citizens to register their weapons, and I'm pretty sure they can constitutionally tax them. I don't even think that the State is limited from requiring people to show some sort of proficiency as a requirement of ownership, after all, the Second Amendment mandates the State to maintain a militia, and the individual has a responsibility to be proficient in the use of his weapon, so that he may bear arms in common defense when necessary. It stops when the government begins enacting laws restricting the ability of the people in general to keep arms.
So, what's left?
Only the definition of "arms" that individuals can "keep", and how does "bear" impact the definition of "keep", as it relates to "arms"?
But that's a subject for another day...I have to get some sleep.