You mean they didn’t take the opportunity in 1874 to cite Vattel and Common Law?
The Minor v Happersett decision said, in part: “The Constitution does not, in words, say who shall be natural-born citizens. Resort must be had elsewhere to ascertain that. At common-law, with the nomenclature of which the framers of the Constitution were familiar, it was never doubted that all children born in a country of parents who were its citizens became themselves, upon their birth, citizens also. These were natives, or natural-born citizens, as distinguished from aliens or foreigners. Some authorities go further and include as citizens children born within the jurisdiction without reference to the citizenship of their parents. As to this class there have been doubts, but never as to the first. For the purposes of this case it is not necessary to solve these doubts.”
Both sides in the Obama eligibility debate have used this citation. Pro-Obama uses the first part and anti-Obama uses the later sentences.