I think it boils down to the simply fact that the term is ambiguous. We have the law of the blood and the law of the land, all wrapped up in a Gordian knot.
RobbyS, how a term recited in over forty Supreme Court Cases, and used as precedent in Minor v. Happersett can be called ambiguous raises the question, “what does ambiguous mean?”
There was never any other definition. Only recently have individuals found the long accepted definition inconvenient. When the author of the naturalization amendment, the 14th, confirmed the Vattel definition, and the most important test case, Wong Kim Ark repeated the Vattel/Minor definition to make Wong Kim, like Obama, a naturalized citizen, naturalized at birth, but naturalized, how can there be ambiguity?