Nations love to go to war, argue leftist pacifists in democratic Western societies. By this account, governments cannot resist the temptation to assert their selfish interests by violent means. Political leaders use the language of just war to hide their real intentions: imperialistic domination and economic profit. These pacifists charge that with the Iraq war, the disastrous consequences of such politics have become hideously clear again.

Anyone committed to this line of thinking will find Nigel Biggar's spirited defense of classic Christian just war theory deeply troubling. Biggar not only argues that the Iraq war was just, but also defends the Allied strategy of attrition in World War I and NATO's bombing campaign against Serbia in 1999. Along the way, he refutes the most sophisticated theological and philosophical criticisms of just war theory. His insights forcefully challenge readers to reconsider their views on war and peace. Whether one finally agrees with Biggar or not, one will think more responsibly, which is indeed Biggar's ultimate goal.

Biggar, Regius Professor of Moral and Practical Theology at the University of Oxford, opens his book by criticizing “the virus of wishful thinking.”Footnote ² He contends that a knee-jerk pacifism has become the dominant position of the German people, the British left, and many Western Christians. Although of different stripes, all these pacifists assume that war is always wrong and peace always possible. Citizens must demand peaceful resolution of every conflict, and political leaders must simply try harder.

Biggar, however, sees deep flaws in both the political judgments and philosophical presuppositions of these peace advocates. Their arguments are politically faulty because some forms of “peace” are worse than war. A refusal to intervene in Rwanda saved the peace for Western nations but resulted in the slaughter of hundreds of thousands of Tutsis at the hands of their Hutu persecutors. Moreover, liberal pleas for peace are philosophically faulty because they make overly optimistic assumptions about human nature. Leftist pacifists in the West refuse to affirm what history so clearly teaches: a nonviolent politics cannot always conquer evil. Their position seems plausible to them only because they live in societies whose military strength has guaranteed economic prosperity and the defense of human rights.

Biggar further develops his position by analyzing scholarly proposals for Christian pacifism. In recent years, the moral thought of Stanley Hauerwas, drawing deeply on Mennonite theologian John Howard Yoder, has insisted that the Christian church is distinctively shaped by Jesus's radical ethic of turning the other cheek and submitting to death at the hands of his enemies. Such a position has also received extensive exegetical support from New Testament scholar Richard Hays. Biggar argues that all three scholars extrapolate beyond the biblical evidence. While the Apostle Paul reserves vengeance to the Lord, he also affirms that human government is a minister of God and has the commission to use coercive means when necessary to protect the innocent and guarantee justice. Christ never condemns soldiers for practicing their vocation, and when he asks his followers to turn the other cheek, he wants them not to ignore injustice but rather to refrain from acts of private vengeance that spring from corrosive and unrestrained anger.

For Biggar, the cross too must be placed in the larger context of God's redeeming purposes. Christ's death is not so much about human nonviolence in the face of evil, but rather about God's active love that seeks human transformation. Pacifists and advocates of just war theory agree that just as Christ died to further God's new order of righteousness, his disciples too must be prepared to die in order to promote good and resist evil. Christian just war theory rests on the further conviction that God sometimes asks Christians to sacrifice themselves lovingly in the course of using violent force to defend those who innocently endure injustice.

Biggar argues, moreover, that those who undertake a just war show love not only to the victims of evil but also to the victims’ persecutors. Just war aims not at destroying wrongdoers but rather at calling them to see the folly of their ways, to repent, and to work for reconciliation with those whom they have harmed. Biggar creatively demonstrates that resentment and retribution, although often regarded as sinful, are Christian virtues when they motivate victims to hold their persecutors accountable. Forgiveness has two levels: first, when victims forgive in order to free themselves from hatred and bitterness, while compassionately recognizing the complex factors that have made their persecutors evildoers; and second, when victims forgive because their persecutors have finally acknowledged and corrected their wrongdoing. Drawing richly from war novels and movies and interviews with soldiers, Biggar persuasively establishes that even soldiers in combat are normally motivated by love, rather than hate—love for their comrades because soldiers want to protect each other from harm, and love for their enemies because soldiers would rather disarm and incapacitate their enemies than kill them.

These considerations lead Biggar to make a distinction between killing that aims simply at eliminating the enemy's life and killing that tragically results because of one's efforts to render the enemy harmless. Discussing classical and contemporary literature on human intentionality, Biggar establishes the soundness of the philosophical principle of double effect and argues that it corresponds to the training that soldiers receive (at least, in most Western countries today) to restrain impulsive anger and hatred and to use only as much force as necessary to accomplish their task. The Christian just war tradition, says Biggar, is deeply concerned with soldiers’ motivations. If one uses force, one must use it for the right reason: out of love to defend victims against unjust aggression, not out of a love of killing.

Having explored the relationship between love and war, Biggar turns to traditional Christian just war criteria. Questions of just cause, legitimate authority, right intention, last resort, proportionality (ensuring that the costs of war will not outweigh the benefits), and the prospects for success arise as a nation considers going to war (ius ad bellum). In prosecuting war (ius in bello), two additional criteria obtain: proportionality (avoiding force more excessive than necessary) and discrimination (minimizing casualties among innocents).

Biggar then applies these criteria to three deeply disputed wars of the past century—the First World War, NATO's intervention in Serbia, and the U.S.-British invasion of Iraq. His research is exhaustive, his argumentation meticulous. While making a case that all three wars were just according to traditional Christian criteria, Biggar also reflects on what each teaches us about the limitations and possibilities of just war thinking.

In regard to World War I, Biggar argues that the aggressive actions of Wilhelmine Germany deeply threatened the democracies of Western Europe. For years, Germany had been seeking a pretext to go to war. Its political and military leaders were driven by a social Darwinism that sought to ensure German domination of the continent by exploiting neighboring nations. Once war erupted, the Germans’ brutal war tactics and repressive rule of occupied populations demonstrated what all of Europe could expect if Germany achieved political hegemony. The Allies had clear and just cause to repel German aggression.

Just cause, however, is not the only criterion of a just war. In the case of World War I, the question of proportionality is especially troubling. Because the Allies could not achieve a quick victory, they prosecuted a war of attrition. By the end of the war, more than ten million soldiers had died. Millions more were wounded or maimed. Some nations lost a quarter of a generation of young men.

Illustrative of issues of proportionality is the Battle of the Somme. Four months of trench warfare resulted in more than six hundred thousand Allied (British and French) dead, maimed, and captured and a comparable number of German casualties. Even after such horrific expense, the Allies gained only six miles. Biggar nevertheless concludes that the costs were ultimately worth the benefits. While criticizing specific Allied strategies that contributed to excessive losses, Biggar notes that the battle succeeded in demoralizing the Germans and exhausting their reserves. It relieved pressure on the French at Verdun and on the Russians on the Eastern Front, and contributed decisively to the ultimate Allied victory.

Biggar concedes that the principle of proportionality is the weakest link in just war thinking. Establishing costs and benefits is difficult after a war ends and nearly impossible ahead of time. Wars inevitably take on a life of their own and have unforeseeable consequences. Establishing proportionality is further complicated by the impossibility of weighing the loss of human life against the good of repulsing injustice and defending democratic freedoms. Arguing for the ultimate value of “human flourishing,” Biggar comes close to saying that if a war is prosecuted for a just cause (i.e., defense of human flourishing against unjust attack), no losses are too great. Only if a nation were to exhaust material resources or political will might one conclude that a war is no longer justifiable. For Biggar, this seems the same as saying that the war would no longer be practically sustainable.

Prior to addressing NATO intervention in Serbia, Biggar undertakes a careful analysis of contemporary philosophical arguments against just war. He responds in particular to David Rodin's groundbreaking book, War and Self-Defense (2002).Footnote ¹ While Rodin frames just war theory primarily in terms of international law and the work of political philosopher Michael Walzer, Biggar turns to what he calls the early Christian just war tradition running from Augustine in the early fifth century to Grotius, Suárez, and Vitoria in the sixteenth and seventeenth centuries. According to Biggar, the weaknesses that Rodin uncovers in just war thinking, such as the absence of a legitimate international authority to authorize war in a global society, do not apply to Christian just war thinking, which asserts a natural moral law that precedes and even trumps positive human law.

This distinction between morality and legality becomes especially important for Biggar's evaluation of NATO's bombing campaign against Serbia. As in his treatment of World War I, Biggar first establishes just cause. Slobodan Milosevič was conducting a campaign of ethnic cleansing against Kosovo Albanians. NATO acted to prevent a humanitarian catastrophe. In response to critics that NATO acted simply out of self-interest—to assert its power against Milosevič's and to save Western Europe from the consequences of political instability in the Balkans—Biggar argues that national self-interest and international humanitarian altruism need not contradict each other. In doing what was best for the victims of grave Serbian injustices, NATO was also doing what was best for the West.

The specific problem that NATO's bombing campaign presents to just war thinking relates to the question of legitimate authority. Because Russia and China blocked Security Council resolutions that would have authorized international intervention, NATO was forced to take action on its own. According to narrow readings of international law, NATO's acts were illegal. Western intervention was nevertheless moral, according to Biggar. Far from undermining international law, appeals to a natural moral law allow individual states to wage war for the sake of furthering international justice when international governing structures, such as the United Nations, are too underdeveloped and weak to act. Biggar further demonstrates that many international lawyers today have come to make just such a distinction between legality and legitimacy.

All these insights come together in Biggar's evaluation of the 2003 Iraq war. From the outset, Biggar acknowledges that his arguments are provocative. He knows that many people in the West now judge the war to have been immoral in justification and disastrous in execution. They angrily accuse the Bush administration of imperialistic ambitions, and Tony Blair of suffering from moralistic megalomania. It is commonly charged that both leaders lied about Saddam's possessions of weapons of mass destruction, violated international law, and were completely unprepared for the task of national reconstruction after invasion. In sum, critics of the war have concluded that “Iraq has been plunged into a state even worse than it suffered under Saddam Hussein, and the costs to the United States and the United Kingdom have far exceeded any gains.”Footnote ²

Biggar believes that the truth is far more complicated. The United States and its allies, he asserts, prosecuted a just war. Even though they were guilty of serious misjudgments in in some of their evaluations and conduct, they fulfilled the basic criteria that the Christian tradition has established. Biggar challenges those who reject the war's legitimacy to make better arguments than they have thus far. He makes his own case by reviewing each of the traditional criteria.

Just cause. Biggar rehearses Saddam Hussein's history of atrocious human rights violations—mass murder of Kurds and other political opponents (perhaps as many as half a million people between 1988 and 2003)—and repeated military aggression (war with Iran, invasion of Kuwait). Saddam's failure to abide by numerous United Nations resolutions calling for disarmament and weapons inspections fueled concern in all major Western governments that he was developing and stockpiling weapons of mass destruction. Because he had used such weapons in the past, the West could expect him to use them again. Evidence of Iraqi government contact with al-Qaida further justified Western concern about Saddam's intentions. Biggar concedes that the failure of invading forces to find weapons of mass destruction severely weakened the allied case for intervening militarily rather than waiting longer. Nevertheless, given what the United States and its allies knew, they could not wait forever. They had just cause to seek regime change before Saddam inflicted further suffering on innocent victims.

Legitimate authority. As in his analysis of NATO and Kosovo, Biggar argues that the Security Council's failure to authorize the use of force demonstrates the ambiguities and limitations of current international law. The United States and its allies were therefore justified in appealing to what was morally right, even though their actions could not receive legal sanction. Biggar argues that the Security Council tacitly recognized the war's moral legitimacy when by a 12–3 vote it rejected a Russian resolution to condemn the allied invasion.

Right intention. Many critics of the Iraq war asserted that the United States was acting out of selfish interests; it wished to protect American access to Iraqi oil and advance American domination of the globe. In carefully reviewing the most relevant evidence, Biggar concludes otherwise. The major U.S. and British actors were focused overwhelmingly on the threat that Saddam posed to his people and neighboring nations. Biggar concedes that the United States and its allies hoped to establish a democratic Iraq that would be friendly to the West. However, this motivation was secondary and, in any case, not dishonorable. As for oil, the principal nation to benefit since the end of the war has been China, not the United States. Moreover, self-interest need not contravene interest in the welfare of others. A nation that sacrifices its own sons and daughters for the sake of freeing others from tyranny brings honor to itself.

Last resort. Biggar argues that the United States and its allies went to war reluctantly and only after numerous United Nations resolutions and a policy of containment failed to win Saddam's cooperation. Critics of war must not use the just war criterion of last resort to induce moral paralysis. In the case of Iraq, the allies could reasonably judge that they had done all that they could, short of military force.

Proportionality (ad bellum). Because, as Biggar has noted, no one can precisely calculate the costs versus the benefits of a war, the best that a decision maker can do “is to consider whether the military and other means seem capable of achieving their end, whether the likely costs in blood and treasure seem tolerable, whether the national interest is sufficiently engaged to maintain enough political support at home, and whether the risk of failure can be borne.”Footnote ³ The allies could reasonably satisfy these concerns as they considered invading. Biggar concedes, however, that haphazard planning for what would follow—the establishment of democracy—resulted in social chaos, which subsequently raised legitimate questions about the costs of regime change in Iraq.

Prospect of success. Biggar argues that despite their naiveté about establishing democracy, the allies could reasonably count on removing Saddam quickly and efficiently. While the postwar Iraqi regime hardly meets Western standards for a well-functioning democracy, it is tolerably good and just—and whatever Iraq's problems today, life is immensely better than under Saddam: as evidence of this claim, Biggar points to “democratically elected governments no longer in pursuit of WMD, accountable to the international community, and responsible to the Shi’ite majority; sufficient political stability and security to host an economic revival; and a semi-autonomous Kurdistan freed from the shadow of state terror.”Footnote ⁴

Proportionality (in bello) and discrimination in waging war. Again noting the difficulty of determining costs and benefits, Biggar concludes that casualties in the Iraq war were not excessive if compared to those of other just wars in recent history, such as World War I. Moreover, evidence establishes that U.S. and British commanders were very concerned to avoid civilian casualties during the invasion. Indeed, many civilian deaths came at the hands of the insurgents, not the allies. Where the allies saw that they had acted with disproportionate harm, they adopted a counterinsurgency strategy that limited civilian casualties. In addition, they prosecuted soldiers guilty of war crimes.

For Biggar, the principal lesson of the Iraq war for just war teaching relates to how one orders and prioritizes the various criteria of just war. He concludes that just cause is far and away the most important factor. A just war is always a defensive action in response to grave injustices against innocent victims. Just cause thus establishes right intention. A just war must proceed from a nation's interest in defending justice, even in cases in which the victims are citizens of another nation. Just cause also decisively determines legitimate authority. Even when legal sanction is absent, a government can legitimate its response to evil by appealing to the natural moral law.

Proportionality, as we have noted, is the most elusive of the criteria. Even just wars are planned and executed by inevitably limited human beings who have what Augustine called “disordered loves.”Footnote ⁵ In the Iraq war, the allies sometimes used excessive force, and the assumption that Iraqis would welcome them as liberators and embrace Western-style democracy was misguided. Nevertheless, a nation's willingness to correct strategic mistakes and moral lapses in the course of war gives evidence of its commitment to justice.

Given how thorough and careful Biggar's work is, it is not possible to assess it accurately without conducting research as thorough as his own. Historians can evaluate Biggar's interpretation of the First World War; philosophers, his arguments in favor of the principle of double effect or against David Rodin's rejection of just war; and experts on international law, his critique of the United Nations. Indeed, at times one wonders whether Biggar is writing to nonexperts at all. General readers, however, will be especially interested in two sets of concerns.

One set of concerns relates to whether Biggar's application of just war criteria is overly tendentious. In his effort to make his arguments airtight, Biggar occasionally acknowledges but rarely concedes alternative ways of reading the evidence. Take the Iraq war. Biggar pays little or no attention to several factors that affected many Americans’ response to Washington's war planning. In relation to just cause, they heard from their government and the mass media much more about weapons of mass destruction and al-Qaida connections than about Saddam's brutal human rights record and his longstanding record of aggression. Biggar does not even mention Colin Powell's presentation to the Security Council, which many observers found unconvincing. If, as Biggar says, the best argument for going to war was to protect the Iraqi people from Saddam, why was the public case for it so muted?

Moreover, Biggar's efforts to project what a leader might do in the future based on what that leader did in the past entail a good bit of speculation. Biggar rejects placing the U.S. prosecution of the Iraq war in a context of a long history of U.S. interventions and invasions aimed at dominating other nations politically and economically, yet insists on judging Iraqi intentions on the basis of Saddam's past behavior. Biggar seems determined to find any argument that he can to implicate Saddam and vindicate the United States.

In relation to last resort, Biggar does not consider options short of full-scale invasion that might have been available to the U.S. and British governments. If containment was not working, what would have spoken for or against a campaign of targeted bombings or establishing greater control of Iraq's borders? While rightly noting that governments cannot wait forever to prosecute justice, Biggar admits that allied misjudgments about weapons of mass destruction became the basis for launching a full-scale invasion with all of its horrendous consequences. Correcting those kinds of mistakes is impossible after the fact.

In relation to right intention, Biggar says nothing about how the United States provided military support to Iraq in the 1980s in its war against Iran, which by some accounts included shipments of materials that could be used for biological and chemical warfare. Did not the United States help build up Saddam, only to turn against him later?

Biggar does not examine the continuing impact of the Vietnam War on how Americans react to their government's arguments for war. Policy makers in the 1960s served up arguments similar to those in 2003: the monstrous human rights violations of Communist regimes (Russia, China, and North Vietnam), the need for the United States to act because the international community would not, and the coherence between American self-interest and defending the South Vietnamese people from external aggression. Many Americans came to believe, however, that their government had lied to them (see the Pentagon Papers), used excessive force (evidenced by the use of Agent Orange, the My Lai massacre, and the bombing of Laos and Cambodia), failed to achieve its ends (the repulsion of Communism and the establishment of a democratic Vietnam), and deeply damaged the nation's international stature.

A second set of concerns relates to the adequacy of the theology that guides Biggar's project. Especially important is his theological anthropology. On the one hand, Biggar criticizes the secular political left for its overly optimistic assumptions about the basic goodness of human nature, as though given enough time and effort, all political differences could be resolved by reason and peaceful means. On the other hand, Biggar regards Reinhold Niebuhr, North America's most commanding social theologian of the twentieth century, as too pessimistic about humans’ ability to work for God's purposes in history. Biggar, unlike Niebuhr, believes that humans can to some degree overcome self-interest in political life.

Biggar claims, rather, to align himself with Karl Barth. Because God is actively redeeming humanity in history, humans can make relatively adequate judgments about justice here and now. At key points, however, Biggar's theology seems more influenced by Christian natural law traditions than by Barth. Biggar argues that humans can discern transcendent moral values. Christian just war criteria therefore accord with the dictates of human reason. If only we think hard enough, we can know what is right.

Biggar's emphasis on humans’ ability to act confidently in history could help Americans be less cynical about their policy makers, who cannot afford moral paralysis and, as Biggar persuasively establishes, often do engage in responsible and rational evaluation of their options. He could be more attentive, however, to the diverse, complex factors that determine what people take to be rational. A central Christian—indeed, more broadly shared religious—insight is that humans grow in wisdom only as they acknowledge the specific social and historical factors (including social location, political ideologies, and personal experiences) that shape and sometimes distort their judgments.

A related issue is Biggar's understanding of sin and evil. Biggar argues that left unchecked, evil tends to wax. In contending against Hitler's fascism, however, Dietrich Bonhoeffer noted that evildoers usually stiffen their backs and dig in their heels when called to account. Punishment sometimes but by no means always promotes self-examination and reformation. Moreover, while human beings must take moral responsibility for their actions, sin usually has social dimensions that implicate others. The harsh conditions imposed by the Treaty of Versailles do not excuse German fascism, but the Allies do bear a measure of responsibility for it. Similarly, in almost every war it takes two to tango. Nations must learn to be as quick to confess their own moral failings as to point out those of others. One wishes that Biggar would say more about the moral culpability of those Western governments that help secure dictators’ power.

Biggar's eschatology also shapes his project. To him, Christian pacifism has too much confidence that God establishes a kingdom on earth apart from the state. Christian pacifists believe that the cross has inaugurated a new era to which the church witnesses by becoming a community of nonviolence and mutual care and love. Refusing to get their hands dirty in worldly politics, they do not recognize that God works through a variety of human actors—including governments—to advance God's redeeming purposes. Biggar regards secular leftist pacifism as defective in a different sense. Because it denies any eschatological reckoning, it calls on humans to establish a kingdom of absolute peace and justice here and now. Biggar insightfully notes that the contemporary reluctance in the West to wage war is related to a fear that no God exists to vindicate those who sacrifice their lives in war out of love for those who suffer injustice.

Biggar wants an eschatology that motivates human action to repel evil in this world, confident of God's ultimate vindication of good. Biggar's position will seem unsatisfying, however, to those who believe that Christians’ first responsibility is to grieve over war and only secondarily to determine its justice. Even the most just war has deeply tragic dimensions that overshadow human reasoning. The arguments of St. Augustine, one of Biggar's heroes, are instructive.

In The City of God, Augustine argues that humans are too limited by their finitude and pride to see clearly what is true and right. The wise judge in a courtroom knows that he is in an impossible situation. Witnesses do not always give true testimony. Wrongdoers may successfully feign innocence, while those who have been falsely accused are sometimes pressured to confess to crimes that they did not commit. Accusers, even when in the right, cannot always prove their claims. Despite realizing that his knowledge is all too limited, the judge must render a decision and call it just. The judge will be deeply distressed, however, by the fact that he sometimes condemns the innocent unawares and frees the guilty.

Augustine argues that political life is no different. Every social group, despite its limited perspective, argues for what it believes to be right and tries to foist it on society as a whole. Some interests prevail at the expense of others. Every political order therefore rests on a degree of injustice. The result is a politics of resentment in which interest groups vie for power and their version of justice. Social chaos is never far away. This kind of peace, says Augustine, hardly deserves the name.

Augustine continues, “The wise man, they say, will wage just wars. . . . [However, if he] remembers that he is a human being, he will rather lament the fact that he is faced with the necessity of waging just wars.”Footnote ⁶ One nation conquers another, always in the name of promoting peace and fellowship. Nevertheless, even when greater peace and fellowship really do result, the price in blood and destruction, says Augustine, should appall anyone who still has feeling. That person will long for a different world.

Nigel Biggar rightly saves us from wishful thinking and moral paralysis. Nevertheless, he writes about the Iraq war a decade after the invasion and acknowledges that he changed his mind several times before coming to his present conclusions. He similarly notes how historians have recently changed their explanations of the causes of World War I. If just war thinking is so complicated after the fact, how much more so when policy makers and citizens stand in the thick of things and events press for decision.

A Christian understanding of war can acknowledge the value of just war thinking, even as it raises a voice of protest against war, even just war. Christians in the tradition of Augustine will long for policy makers to demonstrate greater humility than seems politically expedient, nations to be more repentant of the harm they inevitably inflict in the name of peace and justice, and God to bring about a new heaven and earth in which “death will be no more, mourning and crying and pain will be no more” (Rev 21:4 nrsv). The Christian pacifist tradition that Biggar rejects for its theological and political inadequacies is nevertheless essential in its protest against making war a normal part of human existence. This protest is more than just wishful thinking. Rather, it cries out to God to do what humans apparently cannot.

In his masterpiece, The Warriors: Reflections on Men in Battle, philosopher and World War II veteran J. Glenn Gray invokes the prophetic words of Friedrich Nietzsche:

Nietzsche captures a deeply Christian aspiration. In today's world of terrorist attacks, TSA security checks, NSA surveillance, and CIA killer drones, followers of Jesus will long more than ever for a peaceable kingdom in which the lamb lies down with the lion and humans beat swords into plowshares. In the shadow of the cross, fear and war should no longer have the last word about the human condition. The Christian faith rests on the promise of a deep, abiding transformation of the self that begins even now. Humans groan along with the whole of creation for God to bring it to completion.