However, this section of the majority decision may be the best part of all:
We look to this because it has always been understood that the Second Amendment, like the First and Fourth Amendments, codified a pre-existing right. The very text of the Second Amendment implicitly recognizes the pre-existence of this right and declares only that it "shall not be infringed." As we said in US v. Cruickshank..."this is not a right granted by the Constitution. Neither is it dependent in any manner upon that document for its existence. The Second Amendment declares that it shall not be infringed..."
Absolutely right. The Constitution does not grant us rights; those rights already existed. What it does is restrict how the government can affect those rights. A lot of people (on both the right and the left) seem to forget that, thinking that the Constitution is in fact the sources of these rights.