The idea of empire, once so effectively used by Ronald Reagan to discredit the Soviet Union, has recently undergone a strange rehabilitation in the United States. This process, which started some years ago, has accelerated markedly since September 11. References to empire are no longer deployed ironically or in a tone of warning; the idea has become respectable enough that the New York Times ran an article describing the enthusiasm it now evokes in certain circles. It is of some significance that these circles are not easily identified as being located either on the right or the left. If there are some on the right who celebrate the projection of US power, there are others on the left who believe that the world can only benefit from an ever-increasing US engagement and intervention abroad; for example, in ethnic and religious conflicts (such as those in Rwanda and Bosnia), or in states run by despotic regimes or “rogue” leaders (e.g., Iraq). It is on grounds like these that the idea of a new imperialism has recently been embraced by Britain’s Labour Party.

That elements of the left and the right should discover common ground on the matter of empire should come as no surprise. Contrary to popular belief, empire is by no means a strictly conservative project: Historically it has always held just as much appeal for liberals. Conversely, the single greatest critic of the British Empire, Edmund Burke, was an archconservative who saw imperialism as an essentially radical project, not unlike that of the French Revolution.

The idea of empire may seem too antiquated to be worth combating. But it is always the ideas that appeal to both ends of the spectrum that stand the best chance of precipitating an unspoken consensus, especially when they bear the imprimatur of such figures as the British prime minister. That is why this may be a good time to remind ourselves of some of the reasons imperialism fell into discredit in the first place.

To begin with, empire cannot be the object of universal human aspirations. In a world run by empires, some people are rulers and some are the ruled: It is impossible to think of a situation where all peoples possess an empire. On the other hand, the idea of the nation-state, for all its failings, holds the great advantage that it can indeed be generalized to all peoples everywhere. The proposition that every human being should belong to a nation and that all nations should be equal is not a contradiction in terms, although it may well be utterly unfounded as a description of the real world.

It is precisely the exclusivism of empire that makes it a program for ever-increasing conflict. If the mark of success for a nation consists of the possession of an empire, then it follows that every nation that wants to achieve success must aspire to an empire. That is why the twentieth century was a period of such cataclysmic conflict: emergent powers like Germany and Japan wanted empires as proof of their success. Those who embrace the idea of empire frequently cite the advantages of an imperial peace over the disorder of the current world situation. This disregards the fact that the peace of the British, French and Austro-Hungarian empires was purchased at the cost of a destabiliza-tion so radical as to generate the two greatest conflicts in human history: the world wars. Because of the proliferation of weapons of mass destruction, there can be no doubt that a twenty-first-century empire would have consequences graver still.

An imperium also generates an unstoppable push toward overreach, which is one of the reasons it is a charter for destabilization. This is not only because of an empire’s inherent tendency to expand; there is another reason, so simple as often to go unnoticed. The knowledge that an imperial center can be induced to intervene in local disputes, at a certain price, is itself an incentive for lesser players to provoke intervention. I remember an occasion a few years ago when one of the leaders of a minor and utterly hopeless insurgency asked me: What kind of death toll do you think we need to get the United States to intervene here?

There can be no doubt that political catastrophes can often be prevented by multilateral intervention, and clearly such actions are sometimes necessary. But it is also true that in certain circumstances the very prospect of intervention can, as it were, become an incentive for the escalation of violence. The reason the idea of empire appeals to many liberals is that it appears to offer a means of bettering the world’s predicament. History shows us, unfortunately, that the road to empire is all too often paved with good intentions.