There are various arguments in favour of allowing the civilian possession of firearms (some of which are rather good ones).
However, in the American case, I've always found the constitutional one to be the weakest. It is based upon the US Constitution's Second Amendment:
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.
Whether taken literally or placed within in its historical context, I have always thought that the Amendment deals not with the possession of weapons for any reason, but only in terms of supporting a well regulated militia.
This is not to say that weapon possession for other reasons should necessarily be prohibited, but it does suggest that any 'right' derived from the Second Amendment is limited to a specific purpose.
(An extensive argument against this position can be found here.)
In any case, the Second Amendment's meaning is being revisited by the U.S. Supreme Court as it considers a lower court's decision to strike down Washington D.C.'s strict gun law.
And, apparently, one of the key issues in this case will be...comma placement.
In 'Clause and Effect', Adam Freedman considers the issue, pointing out the argument of the judge who sought to overturn the D.C. ban:
A brief prepared by a group that agrees with the judge's decision has made a similar point:
The decision ... cites the second comma (the one after “state”) as proof that the Second Amendment does not merely protect the “collective” right of states to maintain their militias, but endows each citizen with an “individual” right to carry a gun, regardless of membership in the local militia.
How does a mere comma do that? According to the court, the second comma divides the amendment into two clauses: one “prefatory” and the other “operative.” On this reading, the bit about a well-regulated militia is just preliminary throat clearing; the framers don’t really get down to business until they start talking about “the right of the people ... shall not be infringed.”
Nelson Lund, a professor of law at George Mason University, argues that everything before the second comma is an “absolute phrase” and, therefore, does not modify anything in the main clause. Professor Lund states that the Second Amendment “has exactly the same meaning that it would have if the preamble had been omitted.”In his essay, Freedman looks at the issue of 18th century comma usage and, by way of a little Latin, reaches the following -- fully sensible -- conclusion:
Not that arguments about punctuation are going to convince anyone who already has a strong view on this matter. But still, it's a well-written (and punctuated) essay.
The best way to make sense of the Second Amendment is to take away all the commas (which, I know, means that only outlaws will have commas). Without the distracting commas, one can focus on the grammar of the sentence. Professor Lund is correct that the clause about a well-regulated militia is “absolute,” but only in the sense that it is grammatically independent of the main clause, not that it is logically unrelated. To the contrary, absolute clauses typically provide a causal or temporal context for the main clause.
The founders — most of whom were classically educated — would have recognized this rhetorical device as the “ablative absolute” of Latin prose. To take an example from Horace likely to have been familiar to them: “Caesar, being in command of the earth, I fear neither civil war nor death by violence” (ego nec tumultum nec mori per vim metuam, tenente Caesare terras). The main clause flows logically from the absolute clause: “Because Caesar commands the earth, I fear neither civil war nor death by violence.”
Likewise, when the justices finish diagramming the Second Amendment, they should end up with something that expresses a causal link, like: “Because 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.” In other words, the amendment is really about protecting militias, notwithstanding the originalist arguments to the contrary.
Personally, my favourite collision between politics and punctuation must be Whig MP Richard Brinsley Sheridan's 'apology' to one of his colleagues in the House of Parliament:
"Mr. Speaker, I said the honourable member was a liar it is true and I am sorry for it. The honourable gentleman may place the punctuation where he pleases."
(Courtesy: Eigen's Political & Historical Quotations.)