From Post #117:
The weight of legal and historical authority indicates that the term natural born citizen would mean a person who is entitled to U.S. citizenship by birth or at birth, either by being born in the United States and under its jurisdiction, even those born to alien parents; by being born abroad to U.S. citizen-parents; or by being born in other situations meeting legal requirements for U.S. citizenship at birth. Such term, however, would not include a person who was not a U.S. citizen by birth or at birth, and who was thus born an alien required to go through the legal process of naturalization to become a U.S. citizen. I think that is, at this point, the defacto definition.
Yes, SeekAndFind, this has always struck me as the most obvious and simple definition of NBC. One that most people would intuitively think makes sense. That's not to say it's the right one: there are some alternative ones that have been floated here, and there is some period documentation to support them.