They're going to have to overturn the holding in the recent Supreme Court case, DISTRICT OF COLUMBIA ET AL. v. HELLER then.
Held: 1. The Second Amendment protects an individual right to possess a firearm unconnected with service in a militia, and to use that arm for traditionally lawful purposes, such as self-defense within the home.
That's in the syllabus, rather than the decision itself, but it's also a succinct summary, which was approved by the author of the decision. In any event, Justice Scalia, the author of the opinion, included this phrase:
Putting all of these textual elements together, we find that they guarantee the individual right to possess and carry weapons
But should a new, and liberal, court decide that "right of the people" means "power of the state militias".. well that's the reason for the right in the first place.