[David M. Kennedy teaches history at Stanford University. His most recent book, Freedom From Fear: The American People in Depression and War, 1929-1945, won the 2000 Pulitzer Prize for history. This essay is adapted from his forthcoming book about the distinctiveness of the American national character.]

George W. Bush's 2002 National Security Strategy proclaimed a new American right to wage preventive war. Following the catastrophic events of September 11, 2001, Bush declared, it was simply too risky not to act pre-emptively. Whatever the merits, this doctrine is a radical departure for American diplomacy. At Concord Bridge, Fort Sumter, and Pearl Harbor it was America's adversaries who fired the first shot.

Many critics have berated Bush, accusing him of jettisoning two centuries of tradition and abandoning the high ground from which Americans have historically waged war with stouthearted moral confidence. But although this criticism is valid in many ways, Bush's approach also reaffirms what may well be America's only consistent tradition in foreign policy.

"These values of freedom are right and true for every person, in every society," the National Security Strategy declares. It dedicates the United States to the task of bringing "the hope of democracy, development, free markets, and free trade" to "every corner of the world." Those idealistic—some would say hubristic—words uncannily echo Woodrow Wilson's heady rationale for American participation in World War I. Wilson would recognize George W. Bush as his natural successor, and he would recognize today's Americans as the direct spiritual descendants of the people he so reluctantly led into that conflict. For Wilson did not think that what came to be known, and often derided, as "Wilsonianism" was just a policy selected from a palette of possible choices. Rather, he saw it as the sole approach to international relations that his countrymen would embrace as consistent with their past and their principles. Wilson did not so much invent American foreign policy as discover it....

Woodrow Wilson instinctively reacted to the onset of the Great War by issuing a proclamation of neutrality. But as the conflict grew in scale and duration, wreaking devastation previously unimaginable, he became increasingly convinced that isolation was no longer a viable posture for the United States. Yet Wilson also felt (along with many other Americans) that Theodore Roosevelt's philosophy, with its embrace of raw power and cold national interest, was irrelevant, even alien. If neither traditional isolationism nor conventional realpolitik would do, then it fell to Wilson to craft an authentically American foreign policy that would so resonate in the hearts of his countrymen as to provide a sustainable basis for American international engagement.

Two assumptions underlay Wilson's thinking: that the circumstances of the modern era were utterly novel, and that providence had entrusted America with a mandate to carry out a singular mission in the world. In Wilson's view, the Great War had so conclusively demonstrated the monstrously destructive capacities of modern industrialized states that it had sundered the very fabric of history. The advent of mass democracy, meanwhile, had made modern governments inescapably beholden to their electorates. Avoiding war thus became diplomacy's supreme objective, and attending to public opinion became an indispensable element of statecraft. Wilson therefore concluded—like his great hero, Abraham Lincoln—that the dogmas of the diplomatic past were inadequate to the stormy present. The unprecedented dangers of the twentieth-century world required statesmen to disenthrall themselves from inherited wisdom about international relations—to learn, in Lincoln's words, to think anew and act anew, and to recognize that government of the people necessarily meant involving the people in their government's diplomacy.

But Wilson also believed that America's history offered salvation to the world. Destiny, in his view, had thrust Americans into a role for which their entire past had been but an elaborate rehearsal. Roosevelt had insisted that the United States must shed the delusions nurtured by its peculiar historical development and become a conventional great power. On the contrary, Wilson said, the peculiarities of their history had fashioned for Americans a lever with which they could move the world. The moment had now arrived for the United States to redeem on a global scale the full revolutionary promise of 1776—to create everywhere the novus ordo saeclorum ("new order of the ages") that the founding generation had so extravagantly predicted.

In the end, of course, Wilson failed to wean his country from its propensity to isolation. The Senate rejected the Versailles Treaty and refused to take the United States into the League of Nations. The United States did not merely revert to isolationism in the years after World War I; it entered what was arguably the most isolationist phase of its history. It testily insisted that the Allied governments repay their wartime debts to the United States Treasury, even at the price of gravely disrupting international financial markets and capital flows. It deliberately stood aloof from the gathering crisis that became World War II.

It has long been customary to argue, as Henry Kissinger has done, that Woodrow Wilson failed "because the country was not yet ready for so global a role." There is much truth to that judgment. But in the longer term, when America finally acquired the necessary muscle, Wilsonianism unambiguously triumphed. This has been the central fact of international life since World War II, which conferred on America a power unmatched and unmatchable. Winston Churchill declared in 1945 that "the United States stand at this moment at the summit of the world"—and there the country has remained. In those circumstances America substantially succeeded in remaking the entire international order along Wilsonian lines. Even those carping Europeans embraced Wilson's ways in the end. As the historian Walter Russell Mead has written, "Wilson's principles … still guide European politics today: self-determination, democratic government, collective security, international law, and a league of nations … France, Germany, Italy, and Britain may have sneered at Wilson, but every one of these powers today conducts its European policy along Wilsonian lines."

Even Kissinger, the arch-realist, concedes that "Wilson's principles have remained the bedrock of American foreign-policy thinking." Those principles informed Franklin Roosevelt's Atlantic Charter in 1941. They shaped the array of multilateral institutions that the United States helped to create at the end of World War II, including the International Monetary Fund, the World Bank, and the United Nations, which not only claims America as a member but maintains its headquarters in the nation's principal city. They guided American policy during the long ideological contest with the Soviet Union in the Cold War. And they misguided the United States into the costly conflict in Vietnam....