[wideawake]

(1) Vattel is one of many authorities cited by legal theorists on these questions, not the sole authority in the universe.

(2) Vattel wrote from the perspective of code law and not common law.

(3) Vattel's works were still being revised and updated from his posthumous notes and addenda years after the Constitution was ratified.

(4) The laws of various European states at the time of ratification and the final English edition of Vattel (1797) regarding ius sanguinis and ius soli were, to put it mildly, a patchwork.

[bvw]

Vattel wrote from the perspective of code law and not common law.

That distinction of terms may make sense to you but I think that no Founder would make any sense of it.