... which makes it especially peculiar, that you'd think the Founders would defer to the English law governing subjects of the king, when those men at the Philadelphia Convention were also quite familiar with Vattel.
As well they should have been, since it was Vattel who first coined the term "natural-born citizen," and provided the definition of the term that more than just a few Founders and even early Chief Justices of the Supreme Court cited.
Benjamin Franklin spoke glowingly of the value of Vattel's The Law Of Nations, as did John Jay, as did Samuel Adams much earlier, in the 1760's, and likewise did John Adams and also James Otis of Massachusetts.
Vattel's very definition of the term was cited, nearly verbatim, by John Jay, John Marshall, John Bingham ... I'd say the evidence is far more definitive for Vattel than English common law, as the source for "natural-born citizen."
However, only Vattel defines "Natural Born Citizen." There was simply no other source (known) from where they could have gotten that term defined from.
Or do you agree with Justice Ginzberg that we should refer to foreign law?