Building a new order after November 1989 and, even more, after September 2001, however, is a much harder task. During the Cold War, the Soviet Union created a constraint that disciplined both America's impulse toward withdrawal and excessive ambition. Today the very nature of the threat encourages both temptations. Anarchy and civil war in faraway lands encourage the reluctance to intervene; decentralized fanatical terrorism encourages the temptation to pre-empt. The prospect of "needing" to reform the political culture of nearly the entire Islamic world demoralizes some, energizes others toward nation-building.

The international scene as a whole, too, has become more complex and more difficult to control; other actors have emerged, making it more difficult for the United States either to withdraw from the world or to control its economic and political institutions: reciprocity becomes inevitable and the cost of ignoring it increases. Last, but not least, global issues involving security, the environment or world health increasingly call for multilateral cooperation and institution-building. While the use of force cannot be left to multilateral institutions or to coalitions of the willing, the prevention and resolution of conflicts cannot be left to the unilateral actions of one power, even a benign one.

We are thus left with a structural problem of the international security order-but the American administration seems not to credit the problem at all. It tends toward the primacy of unilateralism and military power, a tendency that surely will harm the legitimacy and the long-term stability of American leadership. What seems to stand in the way of the acceptability of American hegemony, in this respect, are two kinds of exceptionalism: the imperial and the nationalist.

America's imperial exceptionalism consists of a complete asymmetry of rights and duties between the hegemon and the rest of the world, in the refusal to recognize any superior law or authority that might limit its freedom of action. The last ten years have been occupied by the debate between sovereignists and interventionists, the first claiming that the sovereignty of states was and remains the basis of international order, the second that absolute sovereignty should give way to the right of intervention in favor of human rights. The United States seems to have solved this dilemma, as far as it is concerned, by claiming for itself both absolute sovereignty and the absolute right to infringe, including by military force, into the sovereignty of others.

America's exceptionalism offers not only the grandiose face of imperial hubris, but also the narrower one of parochial national interests. Any imperial power has to balance its interests as a nation and its interests as a leader, which include the interests of the system it leads. The Bush Administration, however, seems not to have gotten the hang of this balance. It does not hesitate to abandon its free-trade gospel in favor of the interests of its steel industry or its farmers, or to undermine its own efforts against weapons of mass destruction because of the distaste of its biotech industry for international intrusion. Moreover, while the logic of empire leads ultimately to Caracalla's edict, by which the Roman emperor extended citizenship to all the subjects of his empire, the current American policy pushes to the extreme the distinction between Americans and non-Americans, between the human rights of an American citizen and of an alien, between the value of an American life and that of allied soldiers, let alone of civilian populations or of enemy combatants. This inclination has always existed in the United States-witness Congress's reluctant attitude even toward those international treaties that correspond to American ideas and ideals-but this is an inclination that should be mitigated if America is to rule by invitation and consent rather than by force alone. This is all the more so since Americans are clearly not prepared to undertake the risks and accept the costs-moral and political as well as economic-of direct rule by military occupation.

America's objective should be an international regime that combines its hegemony with respect for international law and multilateral institutions; and those can have no effective role of advice and consent if they do not contain an element of autonomous or non-American power, hence some form of multipolarity. The choice is between an attempt at authoritarian global U.S. rule tempered by anarchic resistance, on the one hand, and, on the other, hegemony tempered by law, concert and consent. What happened last September 11 did not change this choice; it has just made it clearer and more urgent.

Pierre Hassner is the author of many books and essays including Violence and Peace: From the Atomic Bomb to Ethnic Cleansing and the Chaillot Paper The United States: The Empire of Force or the Force of Empire?