This article analyses the mechanics and the political stakes of multilateral trade negotiations in the League of Nations, in the context of the transition from empires to nation states. It examines one attempt to transfer bilateral treaty norms to a multilateral framework, the Draft Convention on the Treatment of Foreigners. This highly contested treaty addressed a policy question that was at the heart of both national sovereignty and international order - the legal treatment of foreign nationals. The attempt to regulate this question on a multilateral basis provoked intense debate about the authority of the League to mediate the relationship between international commerce and national governments.