Christianity has always had a complicated, even paradoxical, relationship to the world. It is, first and foremost, an incarnational faith, which means that it is neither entirely transcendent nor entirely worldly in character. It steadily partakes of both. The Word became Flesh, and dwelt among us. And Christianity departs from its true nature when it leans too much in the direction of one or the other polarity, overemphasizing either the transcendental or the worldly. Both deserve to have their proper weight. And the most influential of the classic Christian heresies are traceable not to wild-eyed distortions but to more subtle errors of imbalance and one-sidedness. Arianism denied Christ’s divine nature; Docetism denied his human nature. Each fell short of the full Christian understanding by failing to embrace the full meaning of the Incarnation.

Christians are to cherish the world, then, and accord it a high degree of respect in keeping with the majesty and dignity of its Maker. This injunction applies not only to the things of nature, which is relatively easy, but also to the things of man, which can be rather more challenging, especially when one is talking about the realm of politics. Yet it is required. It is easy for us to see God’s hand in a beautiful sunset, but rather harder to see it operating at meetings of the local Board of Public Works, let alone the United States Congress. Yet Jesus’ great saying about the need to distinguish between what is Caesar’s and what is God’s is among other things a remarkable endorsement of the legitimacy of secular political authority. As such, it serves as a basis for one of the great distinguishing marks of Christianity: Caesar is accorded his own proper sphere of influence . We sometimes fail to take in the full significance of that fact, even though it is explicitly confirmed in the language of Romans 13. But Jesus’ words also amount to an unyielding declaration regarding the unpassable limits upon Caesar’s authority. So the honor and respect accorded the world, and its worldly authorities, are genuine but finite. And they become wrongheaded, sinful, and idolatrous if allowed to extend further than is their due.

The principle is clear enough. But sorting out the specific and practical implications of this position has always been exceedingly difficult. Just what does it mean, practically speaking, to be in the world but not of it? What are we to do when our Caesars turn vicious or corrupt? Why couldn’t Jesus have given us more specific details, instead of all those elusive parables? Why didn’t he spell out his positions on war, representative democracy, capitalism, the death penalty, term limits, and the Electoral College? We cannot know the reason for the omission, but it seems the better part of wisdom to assume that it was intentional. Christ did not come to put an end to politics”at least not yet. We are not meant to rest easy in a faith that is reducible to a set of neat and inert propositions. We are meant to wrestle with this tense duality of flesh and spirit through all the days of our earthly lives”as Jesus himself did in his own”and in the process we will be forced to fall back on the grace and mercy and unfathomable riches of God for guidance. Somehow, mysteriously, the endless wrestling of flesh and spirit is what shapes the character God wants to build in us, a character both humble and resilient.

As part of this, we wrestle with the meaning of human history. There is no doubt that Christians and Jews accord singular importance to history, since they believe that God’s purposes for humanity are expressed in the unfolding of time. They also believe that God intervenes in human history in ways both large and small”not only, let us say, to decide the fate of great wars, but also to heal the sicknesses of the lowly and bless the marriages of the historically obscure. It is not always clear which of these interventions is the more important, in the context of a faith that constantly delights in ironic reversals of status and contends that the last shall be first, and the first last; and that the stone that was rejected shall become the cornerstone.

In other words, even for a historical and incarnational religion like Christianity, the meaning of human history must sometimes be sought outside of history, where it is revealed rather than discovered. The entire pageant of human history, painstakingly assembled by generations of historians, with all its glittering panoply of great eras, large events, and major figures, may be no more important in the mind of God than the plight of the single sparrow that falls to the earth. Perhaps even less so. We should remember that, and should accordingly have a keen sense of modesty about our grasp of the ultimate meaning of history”and of history’s relation, if any, to the ultimate. We should be diligent in searching for meaning in history, but be modest and skeptical about what we believe we have found therein. After all, we might be wrong. God may have something new and unexpected up His sleeve.

That modesty should extend, I believe, to our efforts to discern rightly the meaning of particular events, such as those that we now denote by the date of September 11, 2001. It may be partly sheer peevishness on my part. But when I hear people like CNN’s Larry King refer to September 11 as “the day that changed America forever,” and when I hear him proclaim that the horrors of that day constitute “the most important event in the history of the United States,” I wince. It’s partly because such portentous statements seem weightless and implausible coming out of the mouths of people for whom “history” is whatever happened two weeks ago, the same people who will be likely to assure us in their next breath that Britney Spears, or some other confection du jour, is the greatest pop singer “of all time.” Imagine that. All time. That term might even span as much as a whole decade.

But more seriously, it seems utterly wrong to say that “everything changed.” I don’t mean in saying this to minimize the shocking character of what happened. But it is possible to be shocked without being surprised. Did we learn something new about human nature on September 11? Something we did not know before about the darkness of the human heart, the danger of our world, or the fragility of our lives? Surely the answer to all these questions ought to be obvious. No, if there is any emotion or impression that ought to predominate in us at this time, it is the sense of having awakened after a deep sleep. For the young”who have lived only through the last two decades of peace and prosperity”the world has indeed changed. But the Larry Kings of the world ought to know better. It is not the world itself, but rather our understanding of the world, that has changed. We woke up.

Christians in particular ought to have the distinct sensation not merely of awakening, but of being reminded of things that they already knew, and might otherwise have preferred to forget. As C. S. Lewis wrote in his splendid 1939 essay, “Learning in War-Time,” the coming of war does not transform life in any fundamental way. Instead, he insisted:

it simply aggravates the permanent human situation so that we can no longer ignore it. Human life has always been lived on the edge of a precipice. Human culture has always had to exist under the shadow of something infinitely more important than itself . . . . We are mistaken when we compare war with “normal life.” Life has never been normal.

War taunts us with overwhelming evidence of our impotence in the face of death”death, both as a reality that each and every one of us faces, and death as a symbol for the ultimate futility of all schemes for earthly perfection and human mastery. For Christians, such a reminder is particularly apropos”even crucial. Lewis well expresses why:

War makes death real to us: and that would have been regarded as one of its blessings by most of the great Christians of the past. They thought it good for us to be always aware of our mortality. I am inclined to think they were right. All the animal life in us, all schemes of happiness that centered in this world, were always doomed to a final frustration. In ordinary times only a wise man can realize it. Now the stupidest of us knows. We see unmistakably the sort of universe in which we have all along been living, and must come to terms with it. If we had foolish un-Christian hopes about human culture, they are now shattered. If we thought we were building up a heaven on earth, if we looked for something that would turn the present world from a place of pilgrimage into a permanent city satisfying the soul of man, we are disillusioned, and not a moment too soon.

Let us leave aside all the speculations about the larger meanings of September 11, many of which have been irresponsible and self-serving, the product of foolishness or opportunism rather than wisdom. Here, by contrast, is a meaning that is plain and unmistakable. Nothing we can say or do can justify the carnage, explain it away, or right the wrong that has been done. But we can at least take away from it all an intensified awareness of our real condition”the bad news without which the good news of the gospel is meaningless. And perhaps with that we can also take away a fresh awareness that the Christian faith can be tougher, more realistic, and more resilient than we ever thought possible”far more tough, realistic, and resilient than its secular competitors.

Plato’s Socrates asserted that the chief aim of philosophy was learning how to die. This is a noble and profound notion, and a challenging one. But it is only a part of the truth. It leans, as all Platonism does, too far to the transcendent side of things. It bespeaks a yearning to escape the pain of impermanence by fleeing the flesh altogether. That is only part of the Christian insight. Even suicide bombers have learned how to die. For us, though, learning how to die must also mean learning how to live . Not only in the heroic moments, when all the light of life suddenly bears brilliantly upon a single point. And not only in moments of profound renunciation or detachment, when the light of the world grows dim and feeble. But also in the texture of ordinary life, when our duties are humdrum, our passions mundane, our horizons diffuse, and no one is watching or keeping score. It also means steadfastly honoring the flesh, not abandoning it, at least not until the appointed time to do so has arrived. Pope John XXIII put it very well, on his deathbed, when he said, “Every day is a good day to be born, every day is a good day to die.” The Christian should be equally prepared for either one. The Christian life is equal parts life and death, death and life, flesh and spirit, tenderness and steel.

Christianity, then, is grounded in a uniquely complex view of our human nature”far more complex, I would argue, than its secular equivalents. And no theologian of the twentieth century has better captured this tensive complexity, and more compellingly rendered the underlying tough-mindedness of the Christian faith, than Reinhold Niebuhr”arguably the outstanding American public theologian of the twentieth century. Niebuhr had an unusually long and productive career, churning out innumerable books, articles, reviews, sermons, speeches, pamphlets, and other writings in the years between the First World War and the Vietnam War. He was not merely a theologian of great distinction, but a public intellectual of the first order, who addressed himself to the full range of public concerns. He had a mind of enormous scope and ambition, and there is hardly an issue of importance”political, social, economic, cultural, or spiritual”that he did not discuss in his many works. His 1952 book, The Irony of American History , is especially relevant at this historical moment. To see why, we must place it in the context of Niebuhr’s broader theological project.

In his youth, Niebuhr was a devotee of the Social Gospel, the movement within liberal Protestantism that located the gospel’s meaning in its promise as a blueprint for progressive social reform, rather than in its assertions about the nature of supernatural reality. Social Gospelers were modernists who had largely dismissed the authority of the Bible and the historical creeds. But they insisted that the heart of the Christian gospel could still be preserved by being “socialized,” i.e., translated into the language of scientific social reform. As Walter Rauschenbusch, perhaps the leading figure in the Social Gospel movement, once put it, “We have the possibility of so directing religious energy by scientific knowledge that a comprehensive and continuous reconstruction of social life in the name of God is within the bounds of human possibility.” The Kingdom of God was not reserved for the beyond, but could be created in the here and now by social scientists and ministers working hand in hand.

Niebuhr soon grew impatient with this kind of talk. He found the progressive optimism undergirding the Social Gospel to be utterly naive about the intractability of human nature, and therefore inadequate to the task of explaining the nature of power relations in the real world. Sin, he concluded, was not merely a byproduct of bad but correctible social institutions. It was something much deeper than that, something inherent in the human condition, something social institutions were powerless to reform. In what was perhaps his single most important book, Moral Man and Immoral Society , published in 1932 in the depths of the Depression, Niebuhr turned the Social Gospelers’ emphasis on its head, arguing that there was an inescapable disjuncture between the morality governing the lives of individuals and the morality of groups, and that the latter was generally inferior to the former. Individuals could transcend their self-interest only rarely, but groups of individuals, especially groups such as nation-states, never could. In short, groups generally made individuals morally worse, rather than better, for the work of collectives was inevitably governed by a brutal logic of self-interest.

Niebuhr dismissed as mere “sentimentality” the progressive hope that the wages of individual sin could be overcome through intelligent social reform, and that America could be transformed in time into a loving fellowship of like-minded comrades, holding hands around the national campfire. Instead, the pursuit of good ends in the arena of national and international politics had to take full and realistic account of the unloveliness of human nature, and the unlovely nature of power. Christians who claimed to want to do good in those arenas had to be willing to get their hands soiled, for existing social relations were held together by coercion, and only counter-coercion could change them. All else was pretense and pipedreams.

This sweeping rejection of the Social Gospel and reaffirmation of the doctrine of original sin did not, however, mean that Niebuhr gave up on the possibility of social reform. On the contrary. Christians were obliged to work actively for progressive social causes and for the realization of Christian social ideals of justice and righteousness. But in doing so they had to abandon their illusions, not least in the way they thought about themselves. The pursuit of social righteousness would, he believed, inexorably involve them in acts of sin and imperfection. Not because the end justifies the means, but because that was simply the way of the world. Even the most surgical action creates collateral damage. But the Christian faith just as inexorably called its adherents to a life of perfect righteousness, a calling that gives no ultimate moral quarter to dirty hands. The result would seem to be a stark contradiction, a call to do the impossible.

But Niebuhr insisted that the Christian life nevertheless requires us to embrace both parts of that formulation. Notwithstanding the more flattering preferences of liberal theologians, the doctrine of original sin was profoundly and essentially true , and its probative value was confirmed empirically every day. Man is a sinner in his deepest nature. But man was not merely a sinner, but also a splendidly endowed creature formed in God’s image, still capable of acts of wisdom, generosity, and truth, and still able to advance the cause of social improvement. All these assertions were true. All have an equivalent claim on the Christian mind and heart. In insisting upon such a complex formulation, Niebuhr was correcting the Social Gospel’s erroneous attempt to collapse or resolve the tension at the heart of the Christian vision of things.

With The Irony of American History , Niebuhr expanded this same tension into a consideration of America’s role in the world. Published at the height of the Cold War, The Irony of American History was a stinging attack on communism-and at the same time, a stinging indictment of American moral complacency, and a warning against the moral failings to which that complacency made America vulnerable. Once again, Niebuhr was fighting on two fronts at once. Indeed, despite his passionate and unyielding opposition to the Communist cause, Niebuhr also believed that the United States resembled its antagonist more than it cared to imagine, and much of the book is devoted to making that case. Americans rightly complained of the Communists’ dogmatic commitment to “philosophical materialism,” the notion that mind is the fruit of matter, and culture the fruit of economics. But, as Niebuhr pointed out, Americans could be said to be equally committed to materialism in practice. “Despite the constant emphasis upon ‘the dignity of man’ in our own liberal culture,” he contended, “its predominant naturalistic bias frequently results in views of human nature in which the dignity of man is not very clear.”

But its materialism was not the greatest of America’s moral dangers. More perilous, Niebuhr thought, was one of our principal points of pride: the deeply entrenched idea that America had a providential mission to fulfill in the history of the world, and that the nation was rendered peculiarly virtuous and innocent by the blessings of that history. Such a conviction permeated the history of the early republic. The Calvinist tradition, exemplified by the Puritans of New England, cast America in the role of a New Zion in the wilderness, a land of spiritual renewal for the entire human race. The Jeffersonian tradition viewed America as nature’s nation, a place free of the encumbrances and tyrannies of older civilizations, where the New Man of a democratic future would be forged. At the core of American national vanity was the conviction that it was the nation of the new beginning. Even Abraham Lincoln, who was a political realist, called America “the last, best hope of mankind,” words that convey the enormous cosmic consequences thought to be at stake in the American experiment.

Niebuhr did not deny the considerable elements of truth behind these assertions of American virtue and preeminence. And he would have been the last person to embrace a facile argument for the “moral equivalence” of the two sides. But he also insisted that the American nation’s belief that it had “turned its back on the vices of Europe and made a new beginning” was not only naive but dangerous. It laid America wide open to the worst dangers of spiritual pride, precisely by blinding it to the failings that have marked its history, as they do any nation’s history. Thus could a source of strength become transformed into a source of weakness. That, in a word, is what Niebuhr meant by the irony of American history”the tendency of American civilization to allow the decency of its motives and the nobility of its intentions to blind it to the sins and errors to which it is prone, and thereby allow its virtue to become the source of its vice.

So, he believed, the nation needed to be more rigorously self-critical in the exercise of its power. If this was all Niebuhr had to say about the matter, though, he would have sounded no different than any number of vocal critics of American civilization, then and now. But he said something more. He added that America also had to act in the world, and do so effectively. Indeed, it had no choice but to do so. Just as the sinful and imperfect Christian is obliged to work intently for the cause of good, despite his incapacities, so a morally imperfect America was and is obliged to employ its power decisively in the world. Opting out is not an option: or rather, it is an option that is just as perilous as the alternatives it would avoid. Niebuhr puts it this way:

Our culture knows little of the use and abuse of power; but we [now] have to use power in global terms. Our idealists are divided between those who would renounce the responsibilities of power for the sake of preserving the purity of our soul and those who are ready to cover every ambiguity of good and evil in our actions by the frantic insistence that any measure taken in a good cause must be unequivocally virtuous.

Needless to say, Niebuhr rejects either of these “idealistic” options, which correspond roughly to attitudes of isolationism and amoral self-righteousness, and continues thus:

We take, and must continue to take, morally hazardous actions to preserve our civilization. We must exercise our power. But we ought neither to believe that a nation is capable of perfect disinterestedness in its exercise, nor become complacent about particular degrees of interest and passion which corrupt the justice whereby the exercise of power is legitimatized.

Be wise as serpents, when needs be, Niebuhr seemed to be saying. But know that you are being serpentine when you so act, and never cease to yearn for the purity of the dove.

Niebuhr concluded Irony by invoking the example of Lincoln, whose Second Inaugural Address near the end of the American Civil War exemplifies the doubleness of vision for which a Niebuhrian statesman should strive. Lincoln’s great speech was notable for its unwillingness to demonize or diminish the soon-to-be-defeated enemy, and for its tempering of moral resoluteness by a broadly religious sense of a larger, imponderable dimension to the struggle. “Both sides,” Lincoln famously declared, “read the same Bible, and pray to the same God . . . . The prayers of both could not be answered; that of neither has been answered fully. The Almighty has His own purposes.” The vantage point of a God who loves all His creatures was vastly greater than that envisioned by any fallible human cause.

Nothing in Lincoln’s words suggests even a hint of faltering in the ultimate goal of destroying the Confederacy and reuniting the nation. And yet, the speech suggests not only Lincoln’s charity for the enemy, but also his keen awareness of the arrogance, blindness, or triumphalism to which his own side was susceptible, flaws that might beget precisely the ironic effects that Niebuhr feared and deplored. That Lincoln himself may not have been entirely innocent of such flaws, and that his conduct of the war necessarily involved him in inflicting wounds that would be painfully slow to heal, only underscores the truth of his words. There was no morally pure path open to him. There never is.

What might we learn from Niebuhr about our current challenges, which are so different from those presented by the Cold War, though similar in requiring patience, persistence, and firm resolution? First and foremost, that it is right and just for Christians to support this war. Indeed, they have an obligation to do so. Niebuhr was no pacifist, and would not have been one in this case. War is one of the instances in which the use of coercive power to counter coercion is tragic but necessary. I suspect that Niebuhr might well approve of President Bush’s remarkably skillful and sensitive handling of the events of the past few months”though perhaps with one notable exception. I suspect that he would not have approved of the President’s frequent use of the language of pure and unadulterated evil to describe our foe. I suspect he would say this for reasons that have less to do with the justice of our cause or the cowardly contemptibility of our foe, than with us. It is not good, he would say, to call Osama bin Laden “the evil one,” a phrase deliberately suggestive of Satan”not so much because our opponent is not evil enough, but because we are not pure enough ourselves, and cannot honestly offer ourselves up as children of light, poised against the children of darkness.

Let me be absolutely clear. I am not here expressing sympathy for the cheap anti-Americanism of the free-riding intellectual elites who disparage our country even as they benefit from its prosperity and freedom. I am not suggesting, as former President Clinton seemed to do, that the legacy of slavery and Indian removal somehow leaves us morally disarmed to act in the present and future. I agree that our cause is just, and frankly feel a thrill of moral satisfaction when I hear our President say so, bluntly and confidently. When the President says, “Let’s roll,” I’m ready.

Yet on September 10 many of us had grave, profound, and well-founded misgivings about the moral direction of our country. The causes of those misgivings did not disappear along with the thousands whose lives were snuffed out on the following day. Once again we are reminded that, for all the talk of radical change, there is also a sense in which nothing has changed.

And so we should not draw the wrong conclusions from the current conflict. We should not imagine that the problems we faced on September 10 have gone away. We should not imagine that, for example, the medical and biotechnological degradation of human life”expressed in everything from abortion, euthanasia, and physician-assisted suicide to human cloning and stem-cell experimentation”has disappeared. We should not imagine that this looming culture of death is what we are fighting for when we fight to preserve Western civilization. We should not fail to see, in fact, that the same prowess we use to defeat mass murderers a world away is threatening us too, arising out of our greatest areas of strength”our scientific and technological skills.

This is precisely the kind of irony that Niebuhr homed in on, a manifest strength that becomes a crippling weakness. And it is only one of many examples one could cite. America’s“quest for happiness,” he wrote, is suffused in irony, precisely because it has been so triumphant. We “succeeded more obviously than any other nation in making life ‘comfortable.’” But we have “tried too simply to make sense out of life, striving for harmonies between man and nature and man and society and man and his ultimate destiny, which have provisional but no ultimate validity.” This has had an ironic result. “Our very success in this enterprise has hastened the exposure of its final limits.” The “naturalistic bias” that has produced a condition in which the very genetic foundations of human personhood are viewed as malleable has indeed led to a view of human nature “in which the dignity of man is not very clear.” Though we are united for now in striking back at a proximate enemy, there are issues within our own house that should not be forgotten in the process, issues whose consequences may be far greater in the long run.

Nor should we allow ourselves to believe that in vanquishing this fanatical religious foe we are striking a comprehensive blow against all forms of “fundamentalism,” making the world safe for secularism. We should be very careful about permitting this war to be so defined, as a war of secular Enlightenment against the darkness of superstition. Here too Niebuhr, who was no fundamentalist, is extraordinarily valuable. For he understood the doctrine of original sin”or more precisely, the Christian understanding of human nature, with its dualities and tensions”as central to American democracy. As Niebuhr often said, it is man’s capacity for reason and cooperation that makes democracy possible”and his susceptibility to sin that makes democracy necessary. Ironically, the doctrine of original sin is the best guarantor of the possibility of the improvement of the human race, since it offers us a truthful and realistic view of the crooked timber of humanity.

Without a broadly biblical understanding of the sources of the dignity of the human person, it is hard to see how that dignity can continue to have a plausible basis in the years to come. And frankly, it is hard to see how our culture, which has become so profoundly post-Christian even within the Church itself, can ever find its way back to that understanding. But that is why hope is not the same thing as optimism. It is not ours to know how that restoration will happen, but rather to contribute what we can toward that objective, and leave the rest to a power beyond our ken. To that end, Niebuhr offers a wonderful formulation, a kind of catechism of theological virtue, to keep it all in perspective:

Nothing that is worth doing can be achieved in our lifetime; therefore we must be saved by hope. Nothing which is true or beautiful or good makes complete sense in any immediate context of history; therefore we must be saved by faith. Nothing we do, however virtuous, can be accomplished alone; therefore we are saved by love. No virtuous act is quite as virtuous from the standpoint of our friend or foe as it is from our standpoint. Therefore we must be saved by the final form of love which is forgiveness.

Here, in the end, we glimpse the essential Christian paradox in a way that seems least paradoxical. For here one sees clearly how the transcendent makes the beauty of the world possible”how what is seen finds its surest grounding in what is unseen. That is precisely the beauty and poignancy of a consecrated life, for it is a lifelong labor to make the visible conform to the invisible. Such labor is a key element in the dignity of man. Yet one also sees how easily such consecration can go astray, when what is unseen is not the unfathomable riches of God, but a presentiment of some earthly perfection, whether it be a comprehensive reordering of economy and society, or a cure for every debility of the flesh. Much better to remember that we live on a precipice, and every human enterprise is inadequate and destined for shipwreck. The knowledge of that, too, is a part of the dignity of man.

Wilfred M. McClay holds the SunTrust Chair of Excellence in Humanities at the University of Tennessee at Chattanooga. This essay is adapted from a Witherspoon Lecture delivered in Washington, D.C.