In a campaign interview last year with the columnist David Brooks, Barack Obama identified Reinhold Niebuhr as his favorite philosopher. Following the president’s Nobel Prize acceptance speech on Dec. 15, many commentators noted that the speech reflected Niebuhr’s Christian Realism, a political theology that stressed the inescapable power of group egoism, especially in nation states, and the need of countervailing power to check injustice in the world. Niebuhr’s major works, Moral Man and Immoral Society and The Nature and Destiny of Man, were sustained arguments for realism in politics and international affairs. But he equally insisted that nations were given to self-deception about their role in the world and employed myths and rationalizations to justify their self-interest.

Indeed, another Niebuhr book, The Irony of American History, offered criticism of the self-deceptions, moral confusions and rationalizations of American foreign policy. Comparing American naïveté to Don Quixote’s, he wrote:

Of all the “knights” of bourgeois culture, our castle is the most imposing and our horse the sleekest and most impressive. Our armor is the shiniest (if it is legitimate to compare atomic bombs with a knight’s armor); and the lady of our dreams is the most opulent and desirable. The lady has been turned into “prosperity.”

Niebuhr was writing of the U.S. struggle against Soviet Communism, but the lesson he drew from the Quixote analogy is eerily applicable to the challenge President Obama addressed in Oslo, the threat of jihadist terrorism. “If only we could fully understand,” he warned, “that the evils against which we contend are frequently the fruit of illusions similar to our own, we might be better prepared to save a vast uncommitted world, particularly in Asia...from being engulfed by a noxious creed.”

In a cold war spirit, the president stood up for the idealistic use of power. “Terrible wars have been fought and atrocities committed,” the president told his audience. “The ideals of liberty and self-determination, equality and the rule of law have haltingly advanced.... It is a legacy for which my own country is rightfully proud.” Later he declared, “The United States of America has helped underwrite global security for more than six decades with the blood of its citizens and the force of its arms.”

There is much in the historic record, especially about World War II and NATO, that provides reason to be proud. In Irony, however, Niebuhr warned against national self-congratulation. “It is characteristic of human nature,” he wrote, “that it has no possibility of exercising power without running the danger of overestimating the purity of the wisdom which directs it.” He would not have been surprised that the two wars since Korea in which the most American blood was shed—Vietnam and Iraq—went unmentioned in the speech.

While President Obama spoke in Oslo before an “Old Europe” audience, with pacifist and internationalist leanings, and invoked the memory of Mahatma Gandhi, Martin Luther King Jr., Nelson Mandela and Pope John Paul II, his speech provided ample reason to believe that his first concern was to placate American critics who quarrel with his talk-first diplomacy and an internationalism that is warmly welcomed overseas.

The Nobel speech was above all an apology for war as a tool for peace. “We will not eradicate violent conflict in our lifetime,” the president said. “There will be times when nations—acting individually or in concert—will find the use of force not only necessary but morally justified.” It was the proclamation of a doctrine right out of the classics of Christian Realism. But as a political philosophy for the 21st century, it was a march backward into cold war history, when the just war was the coin of the realm and “the imperatives of a just peace” were hardly considered.

Developments in international affairs since Niebuhr’s death in 1971 were clustered like an afterthought at the end of the address: accountability to the laws of armed conflict, the design of smart sanctions, nuclear nonproliferation, the promotion of human rights and socioeconomic development. Other recent developments that might have benefitted from a boost on the Nobel platform went unmentioned: nonviolent people’s revolutions, public apologies for national offenses—like President Clinton’s to Rwanda—national reconciliation processes, professional peacebuilding, trials for tyrants and the International Criminal Court. The president was right as far as he went. There is sometimes a place for force in righting injustice. But in Oslo he lost an opportunity to lend the lustre of the peace prize to constructive alternatives to war.