In nations, increasing power seems to bring with it an expanded sense of moral obligation. Until the nineteenth century, for example, famines were considered natural disasters, catastrophes that regimes could palliate but not wholly avert. The Irish potato blight changed that moral calculus. For the first time in history, people had suffered what seemed to be an avoidable famine. While the potato crop would have failed no matter what the British government did, by the 184Os the richest and most sophisticated state in the world had the technical ability to quickly move massive amounts of food across oceans and distribute it to the starving Irish. In the eyes of subsequent generations, the British state, having failed to use this new power, was guilty of an atrocity, and this judgment does not seem obviously wrong; our moral imagination necessarily expands with the increase in our powers.

The degree to which the Western Allies could have averted or significantly limited the Holocaust is a matter of continuing historical debate, but the very possibility that we could have has shaped our moral imagination in the wake of the Second World War. This is in part a result of the sense that the Holocaust was so great and unprecedented an evil that it ought to have broken through political conventions and even “common sense,” but it was also a spillover from the debate over appeasement, which implied that the worst horrors of the Second World War were an avoidable catastrophe. As the Holocaust became the overwhelming symbol of the radical evil that appeasement had permitted, the obligation to forestall future Holocausts by prompt intervention became a thread in debates over political morality and international politics.

As this is written, American pilots are waging a de facto war with Yugoslavia. It seems obvious that the United States has no overwhelming strategic interest in Kosovo. The immediate spur to American intervention here is the memory of our recent inaction during the genocide in Rwanda and the long passivity in the face of atrocities in Bosnia; but the most potent force in play is the memory of the Holocaust. And it is worth noting that despite the increasing European willingness to use military power to rescue the Kosovars, anguish over inaction in the face of genocide seems to be a particularly AngloAmerican phenomenon. When Europeans are confronted with atrocities, their instinct is to respond as humanitarians, not as crusaders. We are different, and the explanation for this difference may lie in the correlation of power and responsibility, and also in divergences of national historical memory. American military power is supreme in the post-Cold War world, and the British abilities at what specialists call “force projection”—the capacity to send one’s military someplace far from home and do a lot of damage when it gets there— while trivial in comparison to America’s, dwarf those of any other power. Whether FDR and Churchill had the knowledge and the