Registration, mandatory inspection of firearms and frequent training were all essential to a well-regulated militia.

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The Founders intended that a well-regulated militia was to be the first, not the last line of defense against a foreign invader or social unrest.

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The firearms used by a well-regulated militia, at the time the Second Amendment was written, were mostly long arms that, like a smaller stockpile of pistols, could discharge only once before they had to be reloaded.

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To decide the case, the justices had to rule directly on the meaning of the Second Amendment, a provision with only 27 words: 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.

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