[pdonis]

> What part of a nuclear warhead wielded by a militia contributes to the security of a free State?

Depends on who's attacking and what might deter them.

> They're useless for guaranteeing your liberties against a tyrannical government

Which is only part of "the security of a free State", not all of it. The militia was also for repelling foreign invasions.

Given our current modern world, I would agree that weapons of mass destruction (nuclear, biological, and chemical) shouldn't be available to anyone who wants them; but the correct legal way to make that happen in the U.S. would be to amend the Constitution to explicitly add that exception to the Second Amendment. As the Second Amendment is currently written, it does not admit of any exceptions. As I noted in another comment upthread, privately owned warships were significant at the time the Second Amendment was passed, and the framers of the Amendment did not exempt them from the category of "arms".