I think we have to make a distinction between a rebellion by a minority and a rebellion by a majority ... yes, militia could be authorized to suppress a rebellion by a minority, but if the rebellion is by a majority, then couldn't the militia be authorized to suppress the government? It seems that in either case the intent would be a free State, where the final authority resides in the body of citizens..In cases of insurrection or rebellion, a Militia can be authorized to disarm an Anarchy or Mob of individuals who keep and bear arms, and are not part of a well regulated Militia.
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The 2A only exempts those individuals who keep and bear arms and who are part of a militia of such individuals. Everyone else, (i.e. an anarchy or mob of individuals who keep and bear arms) is subject to State gun control laws in the State where they reside; and it can be considered part of the traditional police power of a State, to ensure its domestic tranquility and security.
While Heller was definitely a good decision from our point of view, using it to bolster an argument can easily be defeated by simply contending that the SCOTUS was wrong. After all, 4 of the 9 justices voted the other way. Had Heller gone the other way would we be citing it to defend our positions? Of course not. We would be bemoaning the fact that they were a bunch of idiots.
So unless the OP's nemesis is of the type to subborn his argument to "Well, that settles it, the SCOTUS says so." I doubt it would be an effective argument.
Of course to supporters of our form of government that is what must happen when the SCOTUS rules on an issue. Opinions no longer matter. All that's left is a change to the wording of the Constitution by amendment. Good luck with that.