“it means “Born in the US (with exceptions) of parents who are citizens”
OK, but that takes Thomas’s remark even further from establishing this principle. He could have, but didn’t, say that to serve on the Court, you neither have to be born in the U.S. nor even have citizen parents. If he wanted to drive home or even hint to Serrano of his “true” position on NBC, then he would have had to state his point much more clearly than he did.
I do understand your point that under this definition, Thomas’s alluding to the BC itself wouldn’t have been necessary. But that presupposes that Thomas himself knows the “truth” about where Obama was born. You are quite correct if indeed Obama was born in Hawaii (or even Seattle). You are not correct if he was born in Africa or Canada. Absent seeing a carefully vetted copy of the long-form BC, I don’t see how anyone can state with certainty where he was born.
Thus, as a legal strategy, it seems that you first wish to establish definitively his birth location since this alone could be dispositive depending on what the BC actually shows. So getting the long-form BC is step #1 of any sensible strategy to resolve this issue. If it turns out he WAS born in the U.S., you resort to the NBC definition. I concur with your view on the latter, but legally it is not a “slam dunk” (in light of the Wong Kim case). So it would be bad to put all your eggs in the NBC basket and learn that the SC disagrees, especially if it later turned out Obama never was born in the US in the first place.
Tactically, I disagree. If you use the BC issue as your first point of attack, and it turns out that he really was born in Hawaii, you've lost what little credibility you have, and getting anyone to listen to the "1789 meaning" argument will be next to impossible.
But if you make the "1789 meaning" of Natural Born Citizen your main point, it doesn't matter where he was born., and that we really do not know. There is evidence both ways. Not all of it true of course, but evidence none the less.
The only downside to that is that birth abroad might be easier to establish than that the Vattel definition is the one understood by the founding generation. But, in the birth abroad scenario, BHO controls most of the low hanging fruit, the BC, the school records, etc, etc.
I took the 'you don't have to answer that question' remark to mean "you don't have to say if you are a natural born citizen or not"