Vattel was a Frenchman. I don't doubt that some of the Framers were aware of his work, but they were Englishmen or descended from Englishmen. The Framers were writing for other native English speakers and so would have meant whatever the common ENGLISH usage was at the time. This is what the Oxford English Dictionary strives to capture. The fact that they offer no example where parentage and place are both relevant is telling.
ML/NJ
George Washington had a copy of Law of Nations at the Convention.