Shaping things to come.

• Author: Serfaty, Simon

Raymond Aron called the twentieth century "the century of total war," and so it was, arguably the worst ever, exceeding even the devastation created by the Thirty Years' War. As many as 175 million people were deliberately killed, whether in combat or in cold blood--so many on both sides of Europe and throughout the world that it is hard to acknowledge them all. Instead, a selective history of pain and a confining geography of horrors set perverse limits on the casualties we single out over the innumerable others we ignore--each "forgotten" victim an infinity and every overlooked region an offense. Yet, with the United States willing at last to accept the baton of Western leadership from the fallen European great powers, this past century ended, or at least appeared to end, as a triumph of American power and Western values: the very values that Europe had transgressed and the power that America asserted to restore them.

Ten years past the unipolar moment that brought the past century to an early terminus, the traumatic events of September 11, 2001, threatened a new security order, one that transformed George W. Bush, who had preached the virtues of a "humble" foreign-policy approach during his debates with Vice President A1 Gore, into an unabashed unilateralist: "Bring 'em on," as he incautiously put it. Armed with America's arsenal of unmatched capabilities, Bush went to Afghanistan the way Bill Gates would go to McDonald's: with too much money for the place and too little taste for the food. And then, "because Afghanistan wasn't enough ... to make a point that we're not going to live in this world that they want for us," as Henry Kissinger reportedly said, and as Vice President Dick Cheney clearly believed, the war moved on to a new and even more disastrous theater.

The tumult and bloodshed and agony of the past decade have raised the prospect of significant change in American foreign policy and the public conception of the country's role in the world. At stake is nothing less than the conviction that American power and world order are coeval. First announced by President Harry Truman in the doctrine that bears his name, this credo was reformulated periodically throughout the Cold War but never lost its hold on the imagination of the foreign-policy establishment. Mostly forgotten during the Clinton years, when the nation seemed eager to take a time-out, even a vacation, from the world, that doctrine was forcefully reasserted by George W. Bush in two wars to which his name remains affixed and which Barack Obama was elected to end. For no matter how vengeful Americans felt after September 11, the abuses of American power, in Iraq especially, proved increasingly repugnant, and the costs of both wars, including Afghanistan, unbearably excessive.

Paradoxically, a fresh appraisal of the uses of American power gained legitimacy when the evidence of failure forced Bush, too, to recognize its limits: even a power without peers cannot remain a peerless power absent allies that are not only "willing" but also capable and relevant. Indeed, remembering the expectations that prevailed in 2009 little seems more ironic now than the realization that the changes that occurred between Bush's first and second terms in office were more significant than the changes...