Any suggestions?
Vattle is the author of the very influenctial "The Law of Nations or Principles of the Law of Nature Applied to the Conduct and Affairs of Nations and Sovereigns He was Swiss, worked for a German prince, and wrote in French.
The issue here is the Natural Born Citizen term in the eligibility clause of Art. II of the Constitution. Since he wrote in French, he did not write "natural born citizen", but he did write:
Les Naturels ou indigènes font ceux qui font nés dans le pays de Parens Citoyens
Which the early (as in the very next year after he wrote the rather large work) translations converted that to:
The natives or indigenes are those born in the country of parents who are citizens
But the more recent version (1793 or perhaps 1797 and later) say:
The natives, or natural-born citizens, are those born in the country, of parents who are citizens