Guns are not protected by the Constitution. The right to arm oneself - is simply an extension of the right to defend yourself. In a world that contains firearms - that means that individuals have a GOD GIVEN right to defend themselve - with firearms.
Addressing this part specifically - I said "guns" as a shorthand, and to make the argument consistent with the discussion of pools, etc. I really should have said "ownership of guns" which I think means approximately the same thing as the "right to keep...". I have no argument on the pre-existing right. The constitution only confirms and *protects* that right. I'm sticking by the protecting thing, otherwise what is the purpose of the constitution? It's spelled out there in order to protect it.