The right to arm bears,

or something like that. Reproduced from my comment on Matthew Yglesias' blog, and embellished somewhat:

"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."

Grammatically speaking, the Second Amendment is a textbook example of the Nominative Absolute use of the participle, one of the most difficult syntactic features of the English language, something we inherited from our Indo-European ancestors (Greek has similar constructions in the Genitive and the Accusative cases, and Latin has it in the Ablative). Nominative Absolutes are used as a kind of shortcut to combine two sentences. Here's an example, taken from the American Heritage Book of English Usage:

No other business arising, the meeting was adjourned.

What was originally two separate thoughts:

No other business arose. The meeting was adjourned.

have been combined into one sentence. Note that we could have just as easily joined the two by means of a dependent clause. To wit:

Since no other business arose, the meeting was adjourned.

The Nominative Absolute allows you to go one step further, eliminating the dependent clause and its finite verb entirely. This kind of compression, however, comes with a price. Whereas dependent clauses are introduced by adverbs that clue us in to how the two thoughts are logically connected (i.e., "Since"), the Nominative Absolute relies on context alone to make its meaning clear. Generally speaking, it can be read circumstantially - that is to say, as an attendant circumstance to the action of the main verb - in any of the following four ways:

1. Causal. "Since no other business arose, the meeting was adjourned."

2. Temporal. "When no other business arose, the meeting was adjourned."

3. Conditional. "If no other business arose, the meeting was adjourned."

4. Concessive. "Although no other business arose, the meeting (nevertheless) was adjourned."

I'll admit that #4 is a little counter-intuitive, but there are instances in which it might be the best way to read a Nominative Absolute; again, context is key.

But what if the context itself is ambiguous? Let's return to the Second Amendment, which could now be read in any of the following four ways:

"A well-regulated militia, since/when/if/although it is necessary to the security of a free state..."

Clearly the Temporal and Conditional readings of the amendment would have to be unambiguously for gun-control, as they expressly link the right to bear arms to the need for a militia. The Causal reading would also support such a qualification, though hairsplitters could try to say (and do say) that the linkage doesn't necessarily preclude a right to bear arms outside of the context of militia membership. Let's just say that it's a more difficult argument to make grammatically than legally! Only the Concessive reading of the Second Amendment - the most unlikely, mind you - would endorse the idea that gun control is wholly unconstitutional, as it explicitly divorces the one from the other:

"Although a well-regulated militia is necessary to the security of a free state, the right of the people (outside of said militia) to keep and bear arms shall not be infringed."

Such a reading, while not impossible, is a real stretch of English grammar. And yet it is upon this reading - as well as the weakened Causal reading - that the N.R.A. and like-minded folks hang their argument. The funny thing is that Nominative Absolutes are usually employed because from the context they're supposed to be obviously Causal, or obviously Temporal, or obviously Conditional, or obviously Concessive. That the Second Amendment has seemed to be obviously each of these four circumstances to different camps at different moments is one of the most wicked grammatical ironies ever. It makes me wonder if the Founding Fathers - most of whom were familiar with Latin and/or Greek and all of their unusual syntactic features - hadn't deliberately crafted the wording of this amendment to be ambiguous!

I wouldn't put it past them. Especially Thomas "Slick Willy" Jefferson...