Over the past ninety years or so, the American debate about the national interest and the national purpose”the debate about morality and foreign policy”has careened through at least ten cycles, resulting in numerous, and sometimes jarring, shifts in the nation’s approach to the world. The starting point for this cyclical argument coincided with the Great War, as the years from 1914 to 1920 witnessed the emergence, the peak, and the collapse of Wilsonian idealism”an internationalism quite self-conscious in its moral assertiveness, in distinction from the Realpolitik internationalism of Theodore Roosevelt.

The most memorable expression of that idealism came in the April 1917 war message to Congress, in which President Wilson declared that America’s aim in entering the conflagration then consuming Europe was to ensure that the world would be “made safe for democracy.” That such noble sentiments could coexist with a curious political fastidiousness bordering on prissiness, is evident in a less remembered formulation of President Wilson’s”that his interventions throughout the Caribbean and in Mexico were intended “to teach the South American republics to elect good men.” Like Teddy Roosevelt’s Realpolitik internationalism, Wilsonian idealism was shaped by notions of Anglo-Saxon cultural superiority that contemporary progressives would find more than a little embarrassing.

In the immediate aftermath of the “war to end all wars,” Wilsonian idealism was displaced by the “normalcy” of Warren G. Harding and the rise of a strong isolationist current in American politics”a tide of public opinion so formidable that even as strong and crafty a president as Franklin Delano Roosevelt was compelled to tack carefully across it, even as he prepared the United States for its inevitable entry into World War II. American isolationism in those days was another curious business, finding lodgments across the spectrum of political opinion. But whether it was the by-product of Burton K. Wheeler’s progressivist politics, Joseph P. Kennedy’s Anglophobia, Charles A. Lindbergh’s racial and eugenic speculations, or Robert A. Taft’s business-oriented conservatism, isolationism was thought to be finished as a serious force in American public life after December 7, 1941.

The national consensus born at Pearl Harbor was strong enough to permit President Harry Truman, working with Secretaries of State George Marshall and Dean Acheson, and such Republican leaders as Arthur Vandenberg, John Foster Dulles, and Dwight D. Eisenhower, to define and execute a vigilant interventionist internationalism that continued through the Eisenhower, Kennedy, and Johnson administrations (albeit with different strategic and tactical accents, articulated in different registers of moral passion). Although not without its idealist elements, the analytic starting point of this form of internationalism was a realist assessment of the mid-twentieth-century situation: Totalitarianism was a mortal peril to free societies and resisting its aggressive encroachments required the United States to take the lead in defense of the West, since Europe had unmanned itself in the two mid-century world wars.

Such leadership would take American power into lands about which Americans previously knew very little. Still, and notwithstanding considerable costs in blood and treasure, the creators of the postwar internationalist consensus also thought it vere dignum et iustum , “truly right and just” as the Roman Missal says, that the United States take such a leading role in world politics, for, on balance and considering the alternatives, American power was a positive force in the world. The prudent exercise of American power was not only necessary but good , for it aimed at securing the morally worthy goal of peace through freedom. The rhetorical proclamation of that conviction reached its apogee in President Kennedy’s inaugural address of January 20, 1961:

Let the word go forth, from this time and place, to friend and foe alike, that the torch has been passed to a new generation of Americans”born in this century, tempered by war, disciplined by a hard and bitter peace, proud of our ancient heritage”and unwilling to witness or permit the slow undoing of those human rights to which this nation has always been committed, and to which we are committed today at home and around the world. Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe, in order to assure the survival and the success of liberty.

Within five years of President Kennedy’s assassination in 1963, however, the postwar internationalist consensus disintegrated, and isolationism reemerged as a powerful force in American public life: not an isolationism fearful of America becoming contaminated by the world but the isolationism of the New Left, convinced that America itself was poison in and for the world. This new isolationism (which was far more moralistic than anything it found odious in the rhetoric of John Foster Dulles) quickly swept up the Democratic Party, such that, a mere eleven years after Kennedy’s inaugural, the Democratic candidate for president of the United States was urging America to “come home””and being cheered on in that neo-isolationism by the late president’s younger brother and others who claimed JFK’s political mantle.

Meanwhile, the Republican Party under Richard Nixon and Henry Kissinger had adopted a self-consciously realist approach to world politics, drawing on such contemporary intellectual sources as Hans Morgenthau and Albert Wohlstetter and such European historical models as the diplomacy of Metternich and Disraeli. In its pursuit of détente with what some realists judged to be an ascendant Soviet Union, the realism of the Nixon-Ford years downplayed, for instance, human-rights violations behind the Iron Curtain. Yet the Ford administration also negotiated the Basket Three human-rights provisions of the 1975 Helsinki Final Act, which turned out to be a powerful weapon in the hands of human-rights activists throughout the Warsaw Pact countries in the endgame of the Cold War.

In response to the realism of the Nixon-Ford years, a new, morally urgent human-rights activism was born in the mid-1970s within those elements of the Democratic Party aligned with Senator Henry M. Jackson, including pro-democracy social democrats and the trade-union movement. After Jimmy Carter defeated Jackson for the 1976 Democratic presidential nomination and bested President Ford in the subsequent general election, the Carter administration adopted the language of an assertive human-rights policy but filled it with New Left content, aiming its criticism primarily at authoritarian American allies rather than at America’s totalitarian enemies. President Carter’s announcement at Notre Dame in 1977 that Americans had gotten over their “inordinate fear of communism””together with Secretary of State Cyrus Vance’s statement that Carter and Soviet leader Leonid Brezhnev shared “similar dreams and aspirations about the most fundamental issues””demonstrated that the degradation of moral judgment into moral posturing could coexist with breathtaking strategic myopia (and indeed moral blindness) in minds for which the evocation of the specter of Vietnam marked an end to moral reasoning, or indeed any other form of reasoning.

Ronald Reagan challenged the realism of the Nixon and Ford administrations in 1976, but without articulating an alternative strategic vision that drew on the human-rights themes being developed by the Jackson wing of the Democratic Party. That had changed by 1980, thanks in part to the work of Jeane J. Kirkpatrick, Norman Podhoretz, Carl Gershman, Elliott Abrams, and others; their intellectual and policy advocacy filled out the contours of Reagan’s long-standing anticommunism by adding to it the concept of an America once again acting as the international champion of liberty, on the model of Kennedy’s inaugural. The election of Pope John Paul II and his triumphant visit to Poland in June 1979 accelerated Reagan’s sense that the Soviet emperor had fewer clothes than the realists imagined and that the Cold War might actually be won, not simply managed.

The Revolution of 1989 in east and central Europe”a world-historical series of events ignited by moral passion, informed by moral conviction, sustained by deft and morally sophisticated politics, and supported by a resolute demonstration that the Soviet Union could not compete with the United States in a serious arms race”raised further questions about classic foreign-policy realism and its narrow focus on “hard power” as the analytic prism for understanding both the dynamics of world politics and the exigencies of American foreign policy. Nonetheless, the administration of George H.W. Bush restored something of a realist perspective to the White House, through the work of Secretary of State James A. Baker III and national-security adviser Brent Scowcroft. This more conventional approach to the world successfully managed the endgame of the Cold War while effecting the reunification of Germany; it proved far less capable of managing the genocidal dissolution of Yugoslavia or seeing off Saddam Hussein in Iraq.

Then there came the Clinton years, the years when America took something of a holiday from history”and from serious thought about the relation between ideals and realities, moral norms and prudential judgments, in formulating and executing foreign policy. Staffed primarily by veterans of the Carter administration”men and women whose views had first been shaped by the shattering of liberal nerve that forged the McGovernite consensus about Vietnam”the Clinton administration seemed content to test Francis Fukuyama’s notion that history had in fact ended with the triumph of democracy and the free economy in the collapse of European communism between 1989 and 1991. In truth, of course, this blindness was shared across a wide swath of the American foreign-policy community of both parties. Where it could lead was made unmistakably clear on September 11, 2001, after previous signals about history’s implacable turbulence had been insufficiently understood when they erupted in Kenya, Tanzania, and Aden.

President George W. Bush had come to office in January 2001 promising a modest approach to America’s engagement with the world, but the September 11 cataclysm compelled his administration to a profound reexamination of the premises of foreign policy, particularly with reference to the despotic regimes in the Middle East from which so much of the world’s turmoil emerged. Having gone into both Afghanistan and Iraq with the full force of American might, Bush dedicated his second inaugural address, in January 2005, to articulating a “Freedom Agenda” that in its moral passion and political scope was no less breathtaking than the Kennedy inaugural:

We are led, by events and common sense, to one conclusion: The survival of liberty in our land increasingly depends on the success of liberty in other lands. The best hope for peace in our world is the expansion of freedom in all the world.

America’s vital interests and deepest beliefs are now one. From the day of our founding, we have proclaimed that every man and woman on this earth has rights, and dignity, and matchless value, because they bear the image of the Maker of heaven and earth. Across the generations we have proclaimed the imperative of self-government, because no one is fit to be a master and no one deserves to be a slave. Advancing these ideals is the mission that created our nation. It is the honorable achievement of our fathers. Now it is the urgent requirement of our nation’s security, and the calling of our time.

So it is the policy of the United States to seek and support the growth of democratic movements and institutions in every nation and culture, with the ultimate goal of ending tyranny in our world.

And thus we are brought to the latest turn of the wheel, in which the customary positions of foreign-policy idealism and realism have been inverted on the ideological map of American public life. For in reaction to the difficulties of Bush’s second term, and informed by the New Left themes that corrupted the strategic perceptions of the Carter and Clinton administrations, President Obama’s administration spent much of its first year in office proclaiming a “new realism” in foreign policy: a strange hybrid that saw the administration decline to defend human-rights activists in Russia, China, and Iran, apologize for the suffering allegedly caused by American exceptionalism, turn its back on several key allies, and retool human rights to stress “reproductive choice” and what Secretary of State Hillary Rodham Clinton called the imperative of people being “free . . . to love in the way they choose.”

Between Woodrow Wilson and Barack Obama, American foreign policy seems to have averaged one major shift in perspective every 9.5 years, changes influenced both by events in the world and by domestic political exigencies. These shifts have been jarring, but not (yet) fatal, for, in most cases, the American people and their leaders have usually ended up doing what they ought to have done, thus validating Winston Churchill’s observation that the Americans will always do the right thing, after they’ve tried everything else. Nonetheless, oscillations between the idealist and realist poles of the debate over national interest and national purpose create significant difficulties, both within our own political culture and for the world. And thus it is important to understand their sources, with an eye to setting a steadier course.

My proposal is that, while historical circumstances surely played their role, these pendular swings have also been shaped by a defective understanding of how moral truths bear on world politics. At the risk of offending ecumenical proprieties, one significant part of our problem can be defined in these terms: This nation of high moral expectation and deep moral commitments has never had an adequate public philosophy for translating moral truths into a framework for strategic analysis and prudent foreign-policy making”and it has lacked such a public philosophy because the American debate over morality and foreign policy has been dominated by one form or another of an inadequate account of morality that derives from the left wing of the Reformation and its adoption of an Ockhamite, or voluntarist, notion of the moral life.

As John Courtney Murray pointed out in the late 1950s, this Protestant way of conceiving the moral life found good and evil not in the moral structure God built into the world and into us”a structure we could discern by reason”but in the will of God alone. Good is good because God commanded it; Evil is evil because God forbade it. The notion of moral reason finds little purchase here, because reason is untrustworthy, capable of being the tool of passions or interests, both of which are Bad Things.

This Protestant concept of morality also tended to be biblicist, imagining that conclusions about complex issues of public policy could be derived without much exegetical ado from, say, the Sermon on the Mount. It set a high value on motive or intention and was not much concerned with an analysis of possible consequences (the purity of the actor’s will being what most counted)”and thus it was chary of the idea of a “national interest.” As for society, including the passions and interests at play in the world, the individualism endemic to this understanding of morality often led to a curiously apolitical view of public policy: There would be no policy conundra, at home or abroad, if all men would just observe the second Great Commandment (or its secular equivalents).

This was the moralism that dominated American Protestantism in the first half of the twentieth century and that gave rise, by way of reaction, to the neo-orthodoxy of the Niebuhr brothers, on the one hand, and to the foreign-policy realism of Hans Morgenthau and his school on the other. But neo-orthodoxy, despite its powerful critique of moralism and its more trenchant reading of the moral obligations of public authority in the face of the totalitarianism threat, had no solution to the more basic problem of moral reasoning. For it, too, rejected or ignored the classic morality of right reason, substituting for what it found objectionable in the old liberal Protestant moralism such categories as “paradox” or “ambiguity,” all the while trying to maintain its equilibrium in the unresolvable tension between “moral man and immoral society.”

Similarly, the realism of Morgenthau and his school provided no escape from America’s cyclical oscillations between idealism and realism. Realism proved incapable of crafting an adequate analytic lens for reading the signs of the times in the last two decades of the Cold War: Both liberal realists (such as those in the “arms-control community”) and conservative realists missed the dynamics of conscience that made possible the Revolution of 1989. And realism missed those dynamics because its notion of the relation between moral truth and world politics”embodied in Hans Morgenthau’s histrionic claim that “to know with despair that the political act is inevitably evil, and to act nonetheless, is moral courage””was as defective as the moralism it criticized.

If we are to escape the past century’s pattern of an America lurching between an idealism and a realism imagined to be two horns of a dilemma, when they are in fact two dimensions of a single problem, the United States needs a new template for thinking about the national interest and the national purpose. Such a template would give due weight to the defense of the national interest as an inescapable responsibility of government. Yet it would also recognize that securing the national interest must be located within the more ample horizon of a national aspiration to advance what John XXIII in Pacem in Terris called the “universal common good””the pursuit, on the international plane, of the five rationally knowable ends of any morally serious politics: justice, freedom, security, the general welfare, and the peace of order.

Key elements of such a template can be sketched in a series of propositions that I began to develop during the doldrums of the mid-1990s. In the more developed form that follows, they may provide a new intellectual grid for disciplining the American public moral debate in the twenty-first century about the goods to be sought in world politics and the means appropriate to the pursuit of those goods.

1. There is no escape from moral reasoning in politics. Politics, even world politics, inevitably engages questions of good and evil: what is noble and what is base, what is congruent with the truths we can know to be true and what is incongruent with those truths. Thus politics, as Aristotle and much of the classic Western philosophical tradition have long affirmed, is an extension of ethics. This is obviously true of the politics of our domestic affairs; it is also true of world politics, if in a distinctive way. Attempts to subtract or bracket the moral dimension of politics from our calculus of ends and means in the formulation and execution of foreign policy debases public life, warps strategy, and leads to imprudent tactics.

2. History can be bent to reason and will”to the human capacity to know the good, to choose it, and to act on it. Those who deny the possibility of purposefulness in this kind of world”by appeals either to “complexity” or to the “impersonal dynamics of history””have not reflected very carefully on modern history. The twentieth century was replete with examples of purposeful men bending history to their will: Lenin, Hitler, Mao, and Ho Chi Minh are among the odious examples; Churchill, the founders of the State of Israel, Reagan, Thatcher, and John Paul II are among the admirable examples. In the admirable cases, as in the odious ones, concepts of purpose were informed and tempered by issues of interest. Interest and purpose thus seem to be linked, empirically. And this linkage has something of the appearance of a dialectic, in which interest and purpose interact and are thereby mutually refined.

3. The two twentieth-century forms of American moralism are both antithetical to clear thought about the national interest and the national purpose and thus weaken serious statecraft. The traditional, culturally transmitted Protestant understanding of morality in America”voluntarist, subjectivist, biblicist, and individualist”is inadequate to the tasks of moral reasoning and practical action required of statesmen. Its suspicions about the idea of a national interest, like its discomfort with the exercise of power, render it a less than useful counselor to those responsible for the common good, who must try to drive principles into the hard soil of reality while taking care to safeguard the security of those whom they serve.

The secularist moralism that characterized the Vietnam-era New Left and shaped foreign policy in the Carter and Clinton administrations”which looks rather like the old liberal Protestant moralism with God and the Bible tossed overboard”is also inadequate to the tasks of statecraft in the twenty-first-century world. Its ideological distortions preclude our seeing things as they are, which is the essential prerequisite to wise policy. For we cannot advance toward how things ought to be if we do not grasp the nature of things as they are.

4. Neo-orthodoxy’s critique of the older American moralism remains important in devising wise policy in the twenty-first century. The moral sensibility articulated in the pre“World War II Protestant neo-orthodox critique of twentieth-century American Protestant moralism was defined by several imperatives: understanding the inevitable irony, pathos, and tragedy embedded in history; being alert to the dangers of unintended consequences; maintaining a robust skepticism about all schemes of human perfection (especially those in which politics is the instrument of salvation); appreciating democracy without worshipping it. These elements of the neo-orthodox or Niebuhrian sensibility remain essential intellectual furnishing for anyone who would think wisely about interest and purpose in foreign policy.

In the twenty-first century, however, the Christian realist critique of the older American moralism will be less a comprehensive framework and more an important set of cautions essential to the exercise of practical reasoning about America’s action in the world, especially in light of the cyclical return of New Left moralism.

5. Realist conceptions of world politics and foreign policy must be completed by a concept of human creativity in history. Paying close attention to the cautions raised by the realist critique of the older American Protestant moralism and its New Left“influenced successor cannot lead to a form of intellectual paralysis in which the strategist and policy maker simply accept things as they are. Rather, any genuine realism, and certainly any genuine Christian realism, must guard against premature closure in its thinking about the possibilities of human action in this world. Things can change”things can be made to change”for the better. Sometimes.

6. Social ethics, including that subset of social ethics known as “ethics and international affairs,” is a distinctive moral discipline. The moral reasoning appropriate to foreign policy will reflect the distinctive nature of political action. As John Courtney Murray put it, the obligations of society and the state are “not coextensive with the wider and higher range of obligations that rest upon the human person (not to speak of the Christian).” And thus “the morality proper to the life and action of society and the state is not univocally the morality of personal life, or even of familial life . . . . The effort to bring the organized action of politics and the practical art of statecraft under the control of the Christian values that govern personal and familial life is inherently fallacious. It makes wreckage not only of public policy but of morality itself.”

This is a crucial point missed by the old Protestant moralism, New Left moralism, and the approaches to political theology sketched in recent decades by Stanley Hauerwas and representatives of the Radical Orthodoxy school. The moral reasoning appropriate to foreign policy will not apply moral norms appropriate to interpersonal relationships to world politics in a simple-minded, one-to-one correspondence. Rather, the moral reasoning we need will demonstrate to the statesman and policy maker that our choices are not between an immoral or amoral Realpolitik , on the one hand, and naivete on the other; international outlaws are not to be dealt with as one would deal with refractory children, nor are international negotiations exercises in therapy.

By the same token, the moral reasoning we need will keep statesmen and policy makers alert to the possibilities of nudging history in a more humane direction through a variety of means, by keeping public authority’s attention focused on the imperative of pursuing the rationally knowable “universal common good” in our engagement with the world.

7. It is in the American national interest to defend and enlarge the sphere of order in international public life, through prudent efforts at changing what can be changed in the trajectory and conduct of world politics. The irreducible core of the American national interest is composed of those basic security concerns to which responsible public authorities must attend. Those security concerns are not unrelated to a larger sense of national purpose, however: We defend America because America is worth defending, in itself and because of what it means for the world. The security concerns that make up the core of the national interest should not be conceived in classic Realpolitik terms, however; rather, they should be understood as the necessary inner dynamic of the pursuit of the national purpose.

And the larger American purpose in world affairs is to contribute as best we can to the long, hard, never-to-be-fully-realized domestication of international public life: to the quest for ordered freedom, in an evolving structure of international public life, capable of advancing the classic goals of politics (justice, freedom, security, the general welfare, peace). As a matter of hard fact and as a matter of moral truth, the United States cannot adequately defend its national interest without seeking concurrently to advance these goals in the world. As a matter of hard fact and as a matter of moral truth, those goals will not be advanced when they are pursued in ways that gravely threaten the security of the United States.

8. National purpose is not national messianism. The national purpose is a horizon of aspiration toward which our policy (and our polity) should strive. That horizon of purpose helps us measure the gap between things as they are and things as they ought to be, even as it provides an orientation for the long haul. But “national purpose” as defined above is not something that can be achieved in any final sense, because international public life will never be fully domesticated, save under a particularly stringent global tyranny. Understanding national purpose as an orienting horizon of aspiration is a barrier against the cynicism that is the shadow side of realism”and, at the same time, a barrier against the dangers of a moralistic, even messianic, notion of national mission, which implies a far shorter time line and the possibility of final accomplishment.

9. Casuistry is the moral art appropriate to international statecraft. For both the moral analyst and the policy maker, the relation between national interest and national purpose in the practical order is defined through casuistry: the moral art of applying principles to world politics by means of the mediating virtue of prudence. Prudence does not necessarily guarantee wise policy. Prudence does, however, reduce the danger of stupid policy based on moralistic or Realpolitik confusions.

The classic casuistry most in need of renovation in early-twenty-first-century thinking about morality and foreign policy is the just-war tradition, which must be revitalized as a tradition of collaborative reflection on the nature of sovereignty, and on the legitimate sovereign’s use of proportionate and discriminate armed force in the pursuit of peace. Conceptions of the just-war tradition that begin with a prima facie “presumption against war” and that conceive the tradition as a set of hurdles for statesmen to jump through are less than helpful in shaping the kind of reflection required by both the tradition of reason and wise statecraft.

10. The debate over national interest and national purpose is perennial, but not necessarily circular. The dialectic of interest and purpose will remain unresolved. Pursuing a narrow concept of interest without reference to purpose risks crackpot realism. Pursuing grand and noble purposes without regard for safeguarding the national interest risks crackpot idealism, or utopianism. The world being what it is, the temptations of crackpot realism and crackpot idealism may be unavoidable. Succumbing to those temptations is not unavoidable, however, given a clear understanding of the inherently moral character of political choice and the distinctive canons and methods of moral reasoning in the sphere of world politics.

Thus the debate over the right relation between the American national interest and the American national purpose will be a perennial one, given the nature of politics itself as well as the historical character of the American people and their democracy. If it is informed, however, by a proper understanding of the moral reasoning appropriate to thinking about world politics, the argument will not be circular and may yield a measure of wisdom from time to time.

Indeed, had such a template to discipline and guide the foreign-policy debate been in place in the century just past, America might have helped craft a more just and sensible peace settlement after World War I, thus making the rise of National Socialist totalitarianism less likely; America might have found ways to prevent the Soviet absorption of half of Europe after World War II; America might not have abandoned its commitments and its allies in Southeast Asia, thus preventing the bloodbath that followed our withdrawal from the region; America might not have mistaken the threat posed by the Ayatollah Ruhollah Khomeini, described by President Carter’s U.N. ambassador as “some kind of saint”; America might have helped prevent genocide in the Balkans; and America might not have made such a hash of the post-major-combat phases of the Gulf War and the Iraq War.

In politics, as in all things in history, we see through a glass darkly. But the opaqueness can sometimes be broken by the clarity of moral vision that comes from a correct understanding of the nature of morality and of moral reasoning. That understanding is what has often been missing in the American debate over the national interest and the national purpose.

Realist appeals to national interest often assume that we know, intuitively, what that interest is. But we do not. As Charles Frankel, a liberal with some sense, once put it, “the heart of the decision-making process . . . is not the finding of the best means to serve a national interest already perfectly known and understood. It is the determining of that interest: the reassessment of the nation’s resources, needs, commitments, traditions, and political and cultural horizons”in short, its calendar of values.”

Determining the content of the national interest, and the means appropriate to its pursuit, is an exercise in moral reasoning and not merely a political-economic calculation. Therefore, the public debate in America ought to reflect a correct idea of what moral reasoning is and of how the moral reasoning peculiar to international politics functions. The failure to define and culturally instantiate such an idea of moral reasoning is at the heart of our oscillation between foreign-policy idealism and foreign-policy realism.

It is past time for both realists and idealists to recognize that they share a common tendency to reduce morality to something akin to the injunctions of the Sermon on the Mount. The idealists then seek to apply the dominical counsels”poverty of spirit, meekness, mercy, purity of heart”to the business of dealing with everyone from the Dalai Lama to Mahmoud Ahmadinejad and the brothers Castro. The realists, agreeing that these dominical counsels sum up morality, insist that they cannot be applied to states or non-state actors in world politics, concluding that foreign policy is the realm of amorality. Both camps assume that everyone agrees on what morality is and that the real arguments are about the possible or impossible application of that morality to world affairs.

That shared assumption is wrong. As a political culture, we do not know what moral reasoning in foreign policy really means. The morality we need in foreign policy is one whose principles are derived from reflection on the ends of politics as these can be known by reason and whose practices are mediated through the virtue of prudence”the moral craft of applying principle to circumstance so as to maximize the chances of doing good and minimize the dangers of making things worse than they already are. This kind of moral analysis, rooted in the tradition of reason, does not easily yield simple answers. It is, however, the kind of moral reasoning appropriate to the distinctive vocation of the statesman and to the creation of a serious public conversation about the national interest and the national purpose.

Were all of this to be well understood, the oscillation between the idealist and realist poles of American foreign policy would abate, and the future of American foreign policy could be placed on a more steady course”which would be a Good Thing, for us and for the world.

George Weigel is distinguished senior fellow of the Ethics and Public Policy Center, where he holds the William E. Simon Chair in Catholic Studies. This essay is adapted from the Laura B. Jackson Endowed Lecture in World Affairs, delivered at Baylor University on March 23, 2010.