"Amend the amendment".    Actually that would be repealing the amendment. Possible but unlikely.   Has happened before, on the subject of alcohol, but you need a groundswell of clamoring for it--not just blue states.

More likely, as I mentioned earlier, is that the Court will get another gun-related case which deals with the Amendment, and Kennedy will have read some history--and know what he's talking about this time.   So the 5-4 would be the other way.

And the NRA and other gun owners would have to tell us why the 2nd Amendment doesn't require them to show up for regular drills--which it clearly intended to do.