After the Great War, Woodrow Wilson challenged the foundations of international law based on fully sovereign states. “Wilsonianism” as elaborated in the Fourteen Points, and in other speeches, rested on a logic that made a universalized liberal individual the locus of sovereignty in the new world order. The truly radical implications of Wilsonianism had no sterner critic than Robert Lansing, Wilson's secretary of state and one of the founders of the American Journal of International Law. Lansing held tenaciously to a positivist paradigm of international law as it had evolved by the early twentieth century. This article reconsiders the conflict between Wilson and Lansing not so much as a duel between individuals as a duel between conflicting conceptions of sovereignty and the purpose of international law in the new world order.