From the majority opinion:
Putting all of these textual elements together, we find that they guarantee the individual right to possess and carry weapons in case of confrontation. This meaning is strongly confirmed by the historical background of the Second Amendment. We look to this because it has always been widely 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 the right and declares only that it “shall not be infringed.”
We have always had the right to keep and bear arms for personal defense. The Bill of Rights told government that they could not infringe upon this right. In theory that means stupid governors, mayors, presidents and even Ginny Burdick can't tell us what, where, when, how or why we have our guns.