Robert VerBruggen ought not be so impressed by the Henderson dissent in Parker. The argument that the Second Amendment doesn’t apply to DC because the District is not a state is completely implausible, at least from an originalist perspective. The “security of a free State” language was understood at the time of ratification to mean “security of a free country” — as Eugene Volokh notes, it’s a formulation that comes from Blackstone’s Commentaries. Blackstone used “state” as a synonym for “nation,” and so did the Framers; the word “state” is used in that sense in several places elsewhere in the constitution, in reference to “foreign state[s].” And remember that when the constitution was written, the US included the Northwest Territory; does it really make sense to think that the Framers would deliberately deny rights to Americans in that region?
(UPDATE: Robert VerBruggen replies here.–Ed.)