The right is not protected for all persons. It's not even protected for all citizens. It's a right protected for a certain group of individuals for a certain purpose.
Hence, the preamble -- which doesn't limit the right, merely explains it.
Conceding that the Second Amendment secures individual rights, Petitioners nonetheless argue that the term bear arms is exclusively military, such that the Second Amendment right can be exercised only under the direction of a governmental military organization. Putting aside this rather strange concept of rightsa right to particular weapons in an environment where the individual is obliged to obey orders, or a right to defend the government but not oneself or ones familythe text does not support this notion....
To the extent the Second Amendments preamble informs the nature of the operative rights-securing provision, the necessity of a well regulated Militia does not negate, but rather advances the individual character of the right to arms.
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The Militia is constitutionally defined as a preexisting entity, separate and apart from an army or navy that might be raised. U.S. CONST. amend. V (. . . in the land or naval forces, or in the Militia). Congress was authorized both to raise and support a national army and also to organize the Militia. Perpich v. Dept of Def., 496 U.S. 334, 340 (1990). [T]he militia are not troops or standing armies, but civilians primarilyall males physically capable of acting in concert for the common defense. . . . Miller, 307 U.S. at 179.
Who are the Militia? They consist now of the whole people. . . . 3 Jonathan Elliot, DEBATES IN THE SEVERAL STATE CONVENTIONS 425 (2d ed. 1836) (George Mason). That the militia is identical to the people, Akhil Amar, THE BILL OF RIGHTS 51 (1998), is evident from Madisons description of a militia amounting to near half a million of citizens with arms in their hands, who could resist an oppressive standing army. THE FEDERALIST NO. 46, 244 (James Madison) (Carey & McClellan eds., 1990). This militia reflected the advantage of being armed, which the Americans possess over the people of almost every other nation, in contrast to governments [that] are afraid to trust the people with arms. Id.; BOSTON EVENING POST, Nov. 21, 1768, at 2, col. 3 (The total number of the Militia, in the large province of New- England, is upwards of 150,000 men, who all have and can use arms. . . .); NEW YORK PACKET AND AMERICAN ADVERTISER, Apr. 4, 1776, at 2, cols. 1-2 (Whoever asserts that 10 or 12,000 soldiers would be sufficient to control the militia of this Continent, consisting of 500,000 brave men, pays but a despicable compliment to the spirit and ability of Americans).
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The broad civilian understanding of who constitutes the Militia continues today. Congress defines the militia of the United States as comprising all able-bodied males from 17 to 45, who are or intend to become citizens; and members of the National Guard up to age 64. 10 U.S.C. §§ 311, 313.5 Excluded from this definition of Militia, among others, are members of the armed forces, except members who are not on active duty. 10 U.S.C. § 312(a)(3); accord D.C. Code § 49-401 (District of Columbia required to enroll most able-bodied males age 18 to 45 in militia).
In order that the ordinary civilians constituting the Militia might function effectively, it was necessary that the people possess arms and be familiar with their use. After all, individuals called for militia duty were expected to appear bearing arms supplied by themselves and of the kind in common use at the time. Miller, 307 U.S. at 179. Thus, the militia system . . . implied the general obligation of all adult male inhabitants to possess arms, and, with certain exceptions, to cooperate in the work of defence. Id. at 179-80 (citation omitted); see also NEW YORK JOURNAL, May 11, 1775, at 1, cols. 2-3 (recommending to the inhabitants of this country, capable of bearing arms, to provide themselves with arms and ammunition, to defend their country in case of any invasion).
That a militia be well regulated does not mean that it must necessarily be the subject of state control. With respect to troops, regulated is defined as properly disciplined. 7 OXFORD ENGLISH DICTIONARY 380 (1933). In turn, discipline in relation to arms is defined as training in the practice of arms. 3 OXFORD ENGLISH DICTIONARY 416 (1933). Notably, prerevolutionary Americans forming voluntary associations for the purpose of resisting British rule, including Washington and Mason, employed the term well regulated militia to describe their associations. 1 Kate Mason Rowland, LIFE OF GEORGE MASON 428 (1892). These organizations were decidedly not sanctioned by any governmental authority.
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The Second Amendment secures the pre-existing right of the people to keep and bear arms. And it does so, in part, because a militiacomprised of the body of ordinary people proficient in the use of their private armswas deemed necessary. Were the people denied their right to keep and bear arms, they could not function as a well regulated militia.