I always find it fascinating when people go to the "shall not be infringed" part and point out how unambiguous it is.
"Well-regulated militia", however...
Well, "well-regulated" in my mind, might mean that one must have training. Untrained militias, I would imagine, tend to be pretty chaotic.
So, you know, just to play devil's advocate, I'd say that it makes most sense to me to read that language as saying that there should be no infringement on the ability for people to be trained to participate in a well-regulated militia.
While you may be right on the points you mentioned, the 'right to keep and bear arms' is not a subordinate clause to "the well-regulated militia". Therefore, while a militia may need to be trained to be 'well-regulated', the right to keep and bear arms is not dependent upon the existence or regulation of the militia.
Well, the sentence is kind of wonky as it's written, in that there's a comma in there that seems to be misplaced, or something.
The original text reads: "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."
The subject of the sentence, then, seems to be "a well regulated militia." Followed by a dependent clause, separated by commas describing the reason a militia is important. So far, so good. But then, following the rules of modern grammar, what follows should
be a verb plus a complement, e.g. "A well regulated Militia, being necessary to the security of a free state, IS
This isn't what happens, though, which creates some ambiguity.
(And interestingly, following the grammatical logic of that argument, then the verb we're looking for is shall not
... In which case, there's even some argument to be made that the subject of "shall not" is "A well regulated Militia," and not "the right of the people to keep and bear Arms." Reading it that way, the clause about the right of the people to keep and bear arms seems kind of like a weirdly tacked-on bit that doesn't really belong. But I'll leave that one alone.)
One could assume that the first comma is superfluous, in which case the first clause would be all of a piece, and not the subject of the sentence as it originally appears to be. If we do so, the idea would be "A well regulated Militia being necessary to the security of a free state," (in other words, "since a well-regulated militia is necessary to the security of a free state"), "the right of the people to keep and bear Arms, shall not be infringed." (Note that there's a comma after Arms, too, and that further inserts the possibility for ambiguity.)
If we do presume that the correct way to interpret the amendment is the second one, then we still have to contend with two things: One, that the authors chose to put the idea of a well-regulated militia first
in the sentence. In other words, in a stronger, more prominent position. And two, that they even chose to include the language about a well-regulated militia at all. Why didn't they simply write "The right of the people to keep and bear Arms shall not be infringed"?
The fact that they did
include that language, and that they put it in the front of the sentence, in a position of prominence, ought to be considered, or at least not ignored, in discussions of the amendment's meaning.
Constitutional scholars -- people far more knowledgeable about the document than you or I (assuming you're not a constitutional scholar) -- have been examining and debating the language of this amendment for years. Which indicates that, despite the original intent to be as clear as possible, the authors still managed to insert some ambiguity.