....The USG actually mandated that voting citizens own their own longarms and a set amount of powder. It was a government mandate that was actually referred to in the recent healthcare ruling.

That is how it is now, but was that the way it was 200+ years ago? "Canadians are about to overrun us! Who has a gun?"

Constitutional law doesn't work that way. The justification matters. I can think of a few reasons why mandating the purchase of a firearm would be constitutional, but under the same justification, purchasing health insurance would not be.

Doesn't matter.

While an individual may have more rights then those specifically enumerated in the Constitution and it's amendments, said individual does not have the specifically enumerated rights removed because of local or state laws.

So, SCOTUS may eventually decide that every American has a right to affordable, quality healthcare, even if it isn't specifically mentioned in the Constitution(by the by, the 9th Amendment is what allows for this line of thought). They cannot take away specifically mentioned rights, however. And the 2nd Amendment specifically says "the right of the people to keep and bear Arms, shall not be infringed.". Forget about the militia bit before it. Ultimately, that's irrelavent, the right is spelled out and is unambigious. You cannot infringe upon the right to bear arms.

Now, I'd argue that gun registration is not an infringment to the right to gun ownership, just like voter registration isn't.

The problem is that in places like NYC and New Orleans authorities used gun registries to confiscate firearms, even those that were not used in crimes. The scope of these activities has been exagerated IMO, but that it even happens is what makes some gun ownership advocates paranoid.

Uh, precedence matters, but if something uses a justification that doesn't work for the issue at hand, it isn't precedent.

I'd say that the Militia Act falls under the necessary and proper clause, given that Congress is authorized "To provide for organizing, arming, and disciplining, the Militia."

Since there's no such enumerated power to provide for health care, the cases are dissimilar.