In the American foreign affairs tradition, the word ‘humanitarian’ signals at least five important commitments. First, a commitment to engagement with the world, engagement by our government and, perhaps more important, engagement by our citizenry. Secondly, a commitment to multilateralism and intergovernmental institutions. Thirdly, a renunciation of power politics, militarism and the aspiration to empire. Fourthly, a commitment to moral idealism and projects of ethical, spiritual and political betterment for other nations and the world – projects of moral uplift, religious conversion, economic development and democracy. Finally, a commitment to cosmopolitanism – attitudes of tolerance, moderation of patriotism and respect for other cultures and nations – an aspiration that we might rise above whatever cultural differences divide our common humanity.

At this quite general level, these are commitments shared by our allies in European international law, in the world of international human rights, and in the broad United Nations system. These are noble ideas. Yet the history of their transformation into international legal regimes is complex, and made more so by the tensions among these commitments, tensions that leave those who espouse them uneasy about the exercise of power and leadership in the world.

My intention here is to explore some of the difficulties that arise when humanitarian sentiments like these are transformed into legal and institutional projects in human rights, efforts to humanize global trade, and a century of humanitarian efforts to limit the violence and frequency of warfare.