Not true. While the US does not recognize dual citizenship, in most cases it does not prohibit it, nor punish it by loss of US citizenship. At one time, one could lose their citizenship that way, but not for a good long time. There are plenty of US Citizens, natural born and naturalized, who are also citizens of Israel. Many even join the IDF, and still are not stripped of their US citizenship.
The requirement for NBC, apply at birth, not afterwords. They do not involve what another government claims, but they very well could, and IMHO do, involve what the US government recognizes, that is the non-citizenship of the parent(s).
So it doesn't matter if BHO Jr was a British, Kenyan, or Canadian citizen at birth, what matters is the place of birth and the US citizenship, or lack thereof, of his parents.
In your example, if Russia declared that everyone born in Alaska (I changed that to make it a tad more realisti, since we did buy Alaska from them) was a Russian citizen. It would not matter a bit, since the US recognizes them as US citizens, and thus their children born in Alaska would be natural born citizens, Russian claims to the contrary.
“Not true.”
You are right and I’m wrong. Valid point.