Swiss jurist who, in Le Droit des gens (1758; “The Law of Nations”), applied a theory of natural law to international relations. His treatise was especially influential in the United States because his principles of liberty and equality coincided with the ideals expressed in the Declaration of Independence. In particular, his defense of neutrality and his rules for commerce between neutral and belligerent states were considered authoritative in the U.S.

Vattel's work was, as he acknowledged, a popularization of Jus gentium (1749; “The Law of Nations”), by the German philosopher Christian Wolff. Vattel, however, rejected Wolff's conception of a regulatory world state, substituting national rights and duties proceeding from his own view of the law of nature.