For international lawyers, the League of Nations is an institution of great symbolic and doctrinal importance. With its quasi-universal membership (‘universal’ of course heavily qualified), open-ended mandate, and inauguration of an ‘international civil service’, the League broke from the more limited institutional forms of nineteenth-century interstate cooperation, and helped shift ‘international organisation’ from a general aspiration of ordered interaction to a more specific legal category of inter-governmental entities.1 However, the League was an irritant in the international legal order as well as an agent of law’s expansion. It posed new legal questions concerning its own status and personality; the nature of relations with states and others; and the regulation of officials working within it. The emergence of the League thus offers a revealing vantage point on the workings of early-twentieth-century international legal thought, and the modes of analysis we can bring to bear upon it.