A week into the anti-racism protests that followed the chilling murder of George Floyd by a Minnesota police officer, the co-founder of Black Lives Matter (BLM), Patrisse Cullors, appeared on ABC’s Nightline. The show recapped the extraordinary events of that day: US President Donald Trump had announced that he was ‘dispatching thousands and thousands of heavily armed soldiers, military personnel, and law enforcement officers’ to quell the demonstrations. Federal police and military troops had used tear gas, rubber bullets and flash grenades on peaceful protestors gathered around the White House to clear the route to a cynical photo-op: the President posing before a church that he did not enter, holding aloft a Bible that he did not open.

It would be difficult to find a major figure in the history of European political thought who would not have attempted to say something about how authority emerges, or is justified and critiqued, in the world beyond the single polity. Quite frequently, that effort would have involved some idea about a legal order, or at least a set of rules or regularities applicable in that world. Thomas Hobbes was neither the first nor the last major thinker who believed that the ‘international’ realm was characterised by the independence of states existing ‘in the state and posture of gladiators’, thus apparently denying that legal rules or practices or legal thinking could have much relevance therein. Yet others believed, as Immanuel Kant did, that without a constitutional vocabulary not much that was meaningful could be said about the human pursuit of freedom, and that silence about the latter would not only constitute a moral failure but an intellectual and perhaps political mistake. For a long time, the idiom of natural law claimed to offer a universally valid frame for thinking about the nature of the political, as well as providing authority for lawyers’ speculations about the rules and principles governing the conduct of individuals and corporate bodies wherever they might move. The name of the relevant discipline at German universities from the late seventeenth century onwards – ius naturae et gentium, the law of nature and of nations – revealed the full scope of its ambition. That discipline may have died away (although that is a debatable proposition) but any political thinking worth its salt will today (perhaps especially in the twenty-first century) aim to say something about how authority emerges, is maintained or critiqued not only within but also outside the single state. The world of ‘nations’ or even ‘humanity’ is established as an important theme of political and legal speculation.

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.

Many histories of peace settlements in international law have concentrated on the peace treaties of European powers inter se. Literature on the history and anthropology of imperial legal ordering, on the other hand, has illuminated the outer reaches of this picture: peaces made by European powers in the expansion of empire. This chapter draws these two bodies of work into relation, with a particular focus on British practice in the eighteenth and nineteenth century. The chapter poses anew some fundamental questions about the conceptual and juridical universe of 'European' peace-making: to what extent we can understand peace as a relation of law, and where we are to look for the law on peace? Opening up the implicit geographical and conceptual boundaries which characterize much legal scholarship on peace settlements both challenges our sense of the legal past, and offers new insights for thinking about peace-making in the present.