I use this example to illustrate that regular citizens such as ourselves do indeed have the right and duty, and ability, to definitively conclude that the "powers-that-be" can in fact be objectively wrong about the Constitution.
Yes, but only in the sorts of cases that I earlier suggested don't really happen very often. If and when the government passes and enforces a law requiring everyone to turn in anything more dangerous than a set of nail clippers, or we find someone advocating same, then we can know "for a fact" that this position contravenes the Constitution. Short of that extreme, everything else is just arguing about what is and isn't permissible, about where we should draw the line - which is, as I said, a political question, not a Constitutional question.
It should also be apparent that if we're able to agree on this with relatively minimal effort, with a little more effort we should be able to resolve our disagreements about the other aspects of the amendment, as well as other amendments, to the point where we know for a fact that our understanding is correct.
Our understanding of these other aspects being "correct" based on what? Not the Constitution - it's silent about the anthrax versus handguns issue. So what standard do we use to judge our correctness? Or are we, instead, seeking a political compromise that satisfies as many people as possible, without claiming reference to an external standard that, as far as I can see, simply does not exist?
No, I'm taking things one step at a time. Slight difference.
Yes, but only in the sorts of cases that I earlier suggested don't really happen very often.
Don't happen very often? Earlier you were saying that they "don't exist in reality". We're making progress ;-)
Our understanding of these other aspects being "correct" based on what?
Based on applying logic. That means giving the ol' noggon a shake, maybe drinking a cup of coffee, to get the motor up and running. To take an example, you said, "The language of the Constitution is pretty clear that we can't forbid all types of weapon in the hands of the citizenry, and common sense tells us that we can't allow all types of weapons to be available to the citizenry." Common sense does indeed say that, but it doesn't say that the federal government should be the one to prevent the most extreme types of weapons from being available to anyone. Furthermore, nothing in the Constitution grants the feds the power to do that in the first place.
So see? With some effort, we can flesh out the meaning more and more.
...where we should draw the line - which is, as I said, a political question, not a Constitutional question.
If you really believe that, then what business do the courts have getting involved at all? If it's a "political" question, then it should be resolved by the political branches.
If a court can't claim to know for a fact that its ruling is correct, then the ruling deserves no respect at all. If they say to me that what I'm doing is in theory illegal, I think I'd be perfectly justified in telling them to get back to me when they've come to an actual conclusion.