Couple that with the fact that the majority made clear that restrictions on certain types of firearms is still allowable as well as "reasonable" restrictions on places where you can excercise your Second Amendment rights (schools), the decision was gutted and opened-up for liberal shenanigans.
I said this on the day Heller was decided (you can find the posts here on FR) that the decision was not a victory because it could easily result in only allowing single-shot pistols in the home.
The key is putting great judges on the the SCOTUS. That will not happen with a second term of Obama.
At any time in the past the U.S. Supreme Court could have ruled that "arms" are defined as single-shot weapons. But that decision would have only applied to state militia weapons.
After Heller, that decision now would apply to everyone. They have already decided (in the D.C. case) that "keep" means "keep in your home", "bear" means "bear in your home", and "arms" means "handguns".
The right is to KEEP and bear arms. Clearly a tank can be kept. Just like cannons or cannon armed ships could be and were owned by individuals at the time the second amendment was written.
I think Kopel, while being realistic as to what a Court would find, restricts the meaning beyond what was understood by the founders.
It's all about prior restraint. The first amendment does not allow for it, and neither does the second. But both allow for punishing those who misuse the right. To be charged with Conspiracy one must take some action in towards actually carrying out some illegal act. Just talking about it doesn't count.
If the second amendment were enforced in that manner, you could have your tank and ammo for the cannon, but you couldn't fire it in the neighborhood, (endangering others) and you couldn't drive it up on the steps of the Capital and blast away. Or run the tank over your neighbor's cars either.