"the Second Amendment extends, prima facie, to all instruments that constitute bearable arms, even those that were not in existence at the time of the founding" - Caetano v. Massachusetts
2A 保护的其实包括一切单人可以携带的武器,U.S. v. Miller 判词里说,不是军队用的武器还不受保护呢 ......
而且,持武权不源于 2A,也不依附于 2A 而存在。
The right there specified is that of "bearing arms for a lawful purpose." This is not a right granted by the Constitution. Neither is it in any manner dependent upon that instrument for its existence. - U.S. v. Cruikshank