Adams (1787):
"with the other volumes. In the afternoon I took up Vattels’ law of nature and of nations. Emmerich de Vattel, Le droit des gens; ou, principes de la loi naturelle, appliqués à la conduite et aux affaires des nations ... "
http://rotunda.upress.virginia.edu/founders/default.xqy?keys=ADMS-search-1&mode=TOC
Interesting that Adams had no problem reading French and translating "naturelle" into "nature..."
And, please note the date of 1787... Hmmm.. When was the U.S. Constitution ratified again?
Cheers