It may be that for general readers trying to understand the present (as opposed to scholars), Atlantic history goes too far in dissolving the United States into a blurry, ill-defined transoceanic entity -- the might and power of the nation are not about to disappear, nor is the threat posed by its enemies. But because the post-9/11 globalization of American history is really just now taking shape, there is sufficient flexibility at the moment to accommodate a wide range of approaches. Three recent books, for example, offer starkly contrasting visions of America's past and, correspondingly, of its present world role. They are of varying quality but in their different approaches, they point to the kind of intellectual debates we can expect in the future from historians who speak to our current condition.

In "A Patriot's History of the United States," Larry Schweikart, a professor of history at the University of Dayton, and Michael Allen, a professor of history at the University of Washington, Tacoma, self-consciously return to 50's triumphalism, though with a very different purpose from that of the consensus historians. Not interested in irony or in standing outside of history, they are full-blooded participants, self-assured and robust moralists, who argue that the United States is a uniquely virtuous country, with a global mission to spread American values around the world. "An honest evaluation of the history of the United States," they declare, "must begin and end with the recognition that, compared to any other nation, America's past is a bright and shining light. America was, and is, the city on the hill, the fountain of hope, the beacon of liberty." Theirs is a frankly nationalistic -- often blatantly partisan -- text in which the United States is presented as having a duty to lead while other countries, apparently, have an obligation to follow. "In the end," they write, "the rest of the world will probably both grimly acknowledge and grudgingly admit that, to paraphrase the song, God has 'shed His grace on thee.' " This is a point of view with few adherents in the academy these days (let alone in other nations), but it's surely one that enjoys warm support among many red-state conservatives, and in the halls of the White House.

Critics of the Bush administration will find more to agree with in the perspective of " 'A Problem from Hell': America and the Age of Genocide," Samantha Power's Pulitzer Prize-winning history of 20th-century mass murder. Unlike Schweikart and Allen, she does not see virtue inhering, almost divinely, in American history. Instead, she judges that history against a larger moral backdrop, asking how the country has responded to the most dire of international crimes, genocide. The record is hardly inspiring. Power reveals that throughout the 20th century, whenever genocide occurred, whether the victims were Armenians, Jews, Cambodians, Kurds or Tutsis, the American government stood by and did nothing. Worse, in some instances, it sided with the murderers. " 'A Problem from Hell' " exhorts Americans to learn from their history of failure and dereliction, and to live up to their professed values; we have "a duty to act." Whereas Schweikart and Allen believe American history shows that the United States is already an idealistic agent in world affairs, Power contends that our history shows it is not -- but that it should become one.

A third book, Margaret MacMillan's "Paris 1919: Six Months That Changed the World," is in effect an answer to Schweikart, Allen and Power -- an object lesson in the ways American idealism can go wrong. MacMillan's focus is on Woodrow Wilson at the end of World War I. A visionary, an evangelist, an inspiration, an earth-shaker, a holy fool, Wilson went to Paris in 1919 with grand ambitions: to hammer out a peace settlement and confront a wretched world with virtue, to reconfigure international relations and reform mankind itself. Freedom and democracy were "American principles," he proclaimed. "And they are also the principles and policies of forward-looking men and women everywhere, of every modern nation, of every enlightened community. They are the principles of mankind and they must prevail." Other leaders were less sure. David Lloyd George, the British prime minister, liked Wilson's sincerity and straightforwardness, but also found him obstinate and vain. France's prime minister, the acerbic and unsentimental Georges Clemenceau, said that talking to him was "something like talking to Jesus Christ." (He didn't mean that as a compliment.)

As a committed American democrat, Wilson affirmed his belief in the principle of self-determination for all peoples, but in Paris his convictions collided with reality. Eastern Europe was "an ethnic jumble," the Middle East a "myriad of tribes," with peoples and animosities so intermingled they could never be untangled into coherent polities. In the Balkans, leaders were all for self-determination, except when it applied to others. The conflicting parties couldn't even agree on basic facts, making neutral mediation impossible. Ultimately, the unbending Wilson compromised -- on Germany, China, Africa and the South Pacific. He yielded to the force majeure of Turks and Italians. In the end, he left behind him a volcano of dashed expectations and festering resentments. MacMillan's book is a detailed and painful record of his failure, and of how we continue to live with his troublesome legacy in the Balkans, the Middle East and elsewhere.

Yet the idealists -- nationalists and internationalists alike -- do not lack for responses. Wilsonianism, they might point out, has not been discredited. It always arises from its own ashes; it has even become the guiding philosophy of the present administration. Give George W. Bush key passages from Wilson's speeches to read, and few would recognize that almost a century had passed. Nor should this surprise us. For while the skeptics can provide realism, they can't provide hope. As MacMillan says, the Treaty of Versailles, particularly the League of Nations, was "a bet placed on the future." Who, looking back over the rubble, would have wanted to bet on the past?

Little has changed in our new century. Without the dreams of the idealists, all that is on offer is more of the same -- more hatred, more bloodshed, more war, and eventually, now, nuclear war. Anti-Wilsonian skeptics tend to be pessimistic about the wisdom of embarking on moral crusades but, paradoxically, it is the idealists, the hopeful ones, who, in fact, should be painting in Stygian black. They are the ones who should be reminding us that for most of the world, history is not the benign story of inexorable progress Americans like to believe in. Rather, it's a record of unjustified suffering, irreparable loss, tragedy without catharsis. It's a gorgon: stare at it too long and it turns you to stone.