The second amendment to the US Constitution doesn't concern itself with home defense justifications, but only with "we need to scare up a military force, right now". The "right way" to forbid tanks and tac nukes as arms that the people can own would have been to amend the Constitution with something that specifies the limits in some way, but instead we got creative interpretations of "shall not be infringed" to mean "can be infringed as long as a law or agency regulation is produced at either a federal or state level". Which is odd, as GP noted.