A. The shaping of the classical just war tradition

There was, of course, an old and deeply embedded tradition in Western culture that understood war in a very different way from either of the polar opposites I have mentioned. This was the just war tradition. On the terms of this tradition, the use of armed force might serve good or evil depending on whether it was undertaken on the authority of a sovereign, that is, a person or persons responsible for the common good of his/her/their political community, whether it was undertaken to protect that common good, or the broader fabric of relations on which all political communities depended, against injury or the threat of injury, and whether it was undertaken out of a right intention—not to do an injustice to another but to seek to preserve or establish peace. The deepest roots of this tradition reach back into the history of biblical Israel and into the thought and practice of classical Greece and Rome. A specifically Christian version of it traces at least to Augustine in the fourth and early fifth centuries. A coherent and systematic form of this tradition came together in the Middle Ages, over roughly the three centuries from the canonist Gratian's magisterial collection, the Decretum, in the mid-twelfth century to the end of the Hundred Years War in the mid-fifteenth century. At the beginning of the modern period, seminal thinkers from Francisco de Vitoria (1492–1546) to Hugo Grotius (1583–1645) assumed the terms of this tradition and applied them to the political conditions of their own times.

The tradition these thinkers inherited had taken shape as a broad cultural consensus, one whose content had been shaped by inputs from a wide variety of sectors of medieval culture: church law and theology; secular law, including the recovery of the Roman legal concepts of jus gentium and jus naturale; the code of knighthood (the chivalric code); works of political theory, especially the literary tradition defining the responsibilities of the good ruler; and the practical experience of government and of warfare.

In its classic form as it had come together by the end of the Middle Ages, the just war idea consisted of two parts: one defining when resort to armed force is justified (later called the jus ad bellum), the other defining right conduct in the use of armed force (the jus in bello). The jus ad bellum included three requirements: that only someone in sovereign authority, and thus responsible for the common good of the political community, could justly authorize resort to armed force; that there must be a just cause, specifically defense of the common good against serious injury, recovery of something wrongly taken, or punishment of wrongdoing; and that resort to armed force must manifest right intention—not aggression, domination, implacable enmity, just plain cruelty or the like, but the intention to protect, restore, or establish peace. These three requirements corresponded directly with the three ends of good politics in the Augustinian tradition of political thought: order, justice, and peace. Thus defined, the justified use of armed force was understood to be a tool for aiding the achievement of these ends and protecting them when established. All other uses of force were by definition unjust, notably including all uses of armed force by private persons on their own authority and all uses of force manifesting tyrannical intent. The jus in bello included two major elements: a listing of classes of persons who normally, by reason of their personal characteristics (age, gender, degree of mental or physical competence) or social function, were to be regarded as noncombatants and not to be directly, intentionally attacked during a just war; and some rather moribund efforts to define certain means of war as impermissible because of their inherently indiscriminate or disproportionate effects.

B. Development of the just war idea in the modern period

Beginning in the sixteenth and early seventeenth centuries, this unified common tradition broke apart and subsequently developed in separate streams of thought and practice. Grotius effectively began one of these separate streams in his De Jure Belli ac Pacis (1625), where he took the inherited tradition of just war, reinterpreted it in terms of natural law and the common practices of nations, and refashioned it into a theory of the law of nations or international law. Another distinct stream developed within the military sphere, with such writers as Pierino Belli (1502–75) focusing on that portion of the just war tradition having to do with conduct in war and, at the same time, with the emergence of codes of military discipline that remade just war ideas from a system of morality into a set of rules for disciplined conduct under arms. A third stream led into the realm of secular philosophy, eventuating in the “perpetual peace” movement of the Enlightenment era and effectively losing contact with the just war idea as reflecting perennial necessities of statecraft. In the religious sphere, Protestant theology gradually lost conscious sight of just war tradition, while Catholic thought maintained it as a doctrine but generally paid no attention to it.

With the rise of the absolutist state beginning in the seventeenth century, the just war jus ad bellum decayed into the idea of a liberum jus ad bellum, the right of the absolute sovereign to initiate war for reasons of state. At the same time, the requirement of a public declaration of war came to be stressed, so that others could judge the decision to go to war and react as they might. The moral restraints of the just war jus ad bellum thus effectively disappeared, being replaced by calculations of interests and the relative likelihood that other states might respond to a declaration of war by making war against the initiator. At the same time, and perhaps in some sort of compensation for the greater freedom to initiate war implied by the liberum jus ad bellum, greater attention was given to the elements of the jus in bello: protection of noncombatants and limits on the means of war, including both weapons and tactics. The practice of limited war (or “sovereigns' war,” as it has sometimes been called) during the eighteenth century illustrates both these developments. The emergence of both the theory and practice of total war in the early nineteenth century temporarily eclipsed this emphasis on limiting the conduct of war, but by the time of the American Civil War it was once again possible for writers on international law to speak of “the laws and customs of war,” by which they meant effectively the content of the just war jus in bello: avoidance of harm to noncombatants and a sense that the means of war should not be unlimited. The political theorist Francis Lieber's Guerilla Parties (1862) and Code (1863), as well as the U.S. Army's General Orders No. 100 (1863), based on Lieber's Code, put all this into the form of military law and rules of engagement. At about the same time, the first Geneva Convention (1864) put one kind of noncombatant protection—amelioration of the condition of the wounded in armies fighting each other in the field—into the form of an international agreement. The subsequent development of a positive law of armed conflict in international law reflects both Lieber and the first Geneva Convention. In the United States military, General Orders No. 100 (1863) initiated a way of thinking about the government of military forces in combat that has eventuated in the present-day Code of Military Discipline, specific codes of conduct in all the service branches, and increasingly detailed rules of engagement for specific military contexts.

As this illustrates, the military and legal spheres have continued to develop their distinctive approaches to regulating the conduct of war; yet this history also illustrates a substantive dialogue between these two spheres. It also shows the significant continuing presence of just war tradition in both. James Brown Scott in the 1930s, and more broadly the Carnegie Institution's series Classics of International Law, demonstrated the historical linkage between just war tradition and international law at the beginning of the modern period.¹

As regards the resort to war, the picture is somewhat different. Here the convergence has been between international law and the philosophically based version of just war thought that produced the “perpetual peace” literature of the Enlightenment era. That literature sought to limit resort to force by individual states through creating a new super-state structure for international relations, so that only under the authority of the super-state institutions could armed force be rightly used. At the same time, the “perpetual peace” tradition aimed toward abolishing war, seeking instead to settle all international disputes through arbitration. It was but a small step conceptually to the League of Nations (1920), the Kellogg-Briand Pact (1928), and the United Nations (1945). What is lost here is the just war tradition's realistic focus on the possibility of genuine order, justice, and peace only in the context of particular political communities and the tradition's effort to define the use of armed force in terms of the responsibility of the sovereign to protect the common good. The line of development in both this philosophical tradition and in positive international law has responded to the excesses of the absolutist state, which rests on assumptions about sovereignty and international order that can be traced to the Peace of Westphalia in 1648.²

To return more explicitly to the matter of why just war discourse disappeared from moral reflection on war and armed force during the modern period, the developments I have just sketched show how philosophical thought on these matters moved in the direction of an internationalist pacifism. At the same time, there was also a movement in exactly the opposite direction, toward justifying the absolutist state and its totalistic quest for power by whatever means, a movement that produced both Nazism and Stalinism. Taken along with the development of internationalist pacifism, this shows exactly the kind of polarization I identified earlier, between rejection of war as such as inherently evil and an embrace of total war. In the United States, internationalist pacifism became an important element in the pacifistic rejection of all war, while the reaction to Nazi and Stalinist totalitarianism fueled the idea that war against such enemies—and by extension, all war—should be prosecuted without limits.

Religious moral thought, as I indicated earlier, effectively forgot its just war heritage over the course of the period from the seventeenth century through the middle of the twentieth, following along the same lines as sketched out above for internationalist philosophy and international law. At the same time, other forms of pacifism unique to the religious context also grew. Christianity has a long tradition of sectarian, or world-rejecting, pacifism. In not entirely self-consistent but psychologically persuasive ways, sectarianism's critique of the state could recognize common cause with the critique of the state in internationalist utopianism. British historian Martin Ceadel has studied this closely for Christian pacifism in England in the context of the two World Wars; what he found was convergence of very unlike forms of pacifism prior to the wars, followed by a falling apart of the convergence during the wars themselves, and then a coming together again after the wars ended.³

C. The contemporary recovery of the just war idea

It is possible to identify three important benchmarks in the contemporary recovery of the just war idea. The first is the work of Paul Ramsey in the 1960s. In two books, War and the Christian Conscience⁴

In entering the secular policy debate, Ramsey shifted his language somewhat. There he argued that both the permission to use force and the limitation on such force follow from the nature of politics itself: as he put it, force “is inseparable from politics' proper act of being politics, inseparable from the well-being of politics, inseparable from the human pursuit of the national or the international common good by political means.”⁷

Ramsey only relatively infrequently drew out elements of his jus ad bellum and never developed it systematically, arguing that the choice to resort to force is a matter for good statecraft, not for a moral theoretician. Yet he had no inhibition about developing at length the implications of his jus in bello, which he regarded as bearing not only on the policy sphere but also on the sphere of personal morality. The result was a somewhat one-sided just war theory that spoke powerfully and directly about the obligation not to harm noncombatants and to limit overall destruction but only treated the question of moral resort to force in general terms.

Ramsey also did not seek to engage the historical just war tradition in his effort to recover the just war idea. He wrote as a theologian interpreting a fundamental Christian theological ideal and as a political philosopher interpreting classical understandings of politics. This is evident, I suggest, in his definition of the limits to be observed in using force by means of two moral principles, whereas the classical tradition had defined its limits in terms of concrete listings of categories of persons not normally to be targeted in war and concrete efforts to ban or restrict specific means of war. Military and legal usage, as I have shown above, held on to the language and method of the classical just war tradition on the jus in bello, but Ramsey, reaching back over the historical tradition to the theology of Augustine, produced a more generalized and simultaneously more abstract conception of the jus in bello.

While Ramsey's work initiated the recovery of just war thinking in American moral discourse on war, the particular form and focus of his work also left a legacy of problems for that discourse as it has subsequently developed. Two problems in particular should be noted. The first follows from Ramsey's reliance on the idea of moral principles rather than the concrete restrictions found in the historical tradition. While the principle of discrimination translates fairly directly into identifying classes of noncombatants who should never be directly, intentionally targeted, its lack of specificity left the door open for arguments that in modern war there are no noncombatants. The difficulty for the principle of proportionality has been that the concept is harder to keep focused. As a result, in subsequent usage the concept of proportionality has been made to mean essentially whatever one might want it to mean in a given argument. The second problem follows from Ramsey's emphasis on the jus in bello and relative lack of focus on the jus ad bellum. This has opened the door to a widespread phenomenon in recent just war discourse, making the jus in bello categories do jus ad bellum duty. Specifically, some have argued, if discrimination and proportionality are moral obligations in the use of force, then if they are not observed or cannot be expected to be observed, there can be no just resort to force. Ramsey himself opposed this line of argument, calling it a bellum contra bellum justum, that is, a “war against just war.” Nonetheless, it has provided a powerful tool in the hands of opponents of nuclear weapons and of all modern war as inherently indiscriminate and disproportionate, and thus never able to be just.

The second major benchmark in the recovery of just war thinking for American moral discourse on war is Michael Walzer's 1977 book Just and Unjust Wars.⁸

The publication in 1983 of the United States Catholic bishops' pastoral letter The Challenge of Peace provides the third major benchmark in the recovery of just war thinking in American moral discourse about the use of armed force.¹⁰

The bishops began with what has become a trademark idea for them: that Catholic teaching “establishes a strong presumption against war.”¹¹

The specific list of jus ad bellum criteria provided in The Challenge of Peace differs in important ways from the traditional listing. As I have noted, the classical jus ad bellum included three requirements: sovereign authority, just cause, and right intention (the end of promoting peace), a formulation already settled by the time of Aquinas. These three requirements correlated directly with the ends of good politics as conceived in Augustinian political theory: order, justice, and peace. It was important for classical just war tradition to put the jus ad bellum requirements in this order, because doing so expressed a priority: only one in sovereign authority could justly employ force, and he could do so only in pursuit of justice and for the end of peace. The Challenge of Peace, by contrast, lists the jus ad bellum criteria as follows: just cause, competent authority, comparative justice, right intention, last resort, probability of success, and proportionality.¹⁴

As for the bishops' treatment of the jus in bello, I have already discussed how, in the classical just war tradition, the matter of moral limitation on conduct in war was approached in two ways: by defining specific classes of people normally to be regarded as noncombatants because of personal characteristics or social function, and thus not made the object of direct, intended harm in war; and by setting restrictions on the means of war. As I have also already noted, international law and military tradition have taken shape around the same two approaches. The Challenge of Peace, however, adopted the language of Ramsey, defining its jus in bello through two principles, which it listed in reverse order from Ramsey's: proportionality and discrimination. The context of the discussion makes clear why the bishops placed proportionality first: “the destructive capability of modern technological warfare” and the expectation that any war, “however initially limited in intention and in the destructive power of weapons employed,” would escalate to “the use of weapons of horrendous destructive potential.” As a result, the bishops judged, “today it becomes increasingly difficult to make a decision to use any kind of armed force.”¹⁶

Whereas Ramsey's and Walzer's influence had up to this point been largely limited to relatively narrow religious, intellectual, and policy circles, The Challenge of Peace had a far broader impact. The drafting committee held public hearings and heard testimony from a wide variety of types of people, including representatives of the Reagan administration. The second draft of the pastoral letter made the front pages of both the Washington Post and the New York Times, where its text was printed in its entirety. Numerous colleges and universities held conferences and hosted talks relating to the developing pastoral letter and the larger topic it dealt with. The U.S. Army's annual conference of its major command chaplains—the colonel-level chaplains assigned to the Army's various major command regions throughout the world—included a focus on this developing statement and what its implications might be for a military whose membership was very heavily Catholic. After the final version of The Challenge of Peace was adopted, the United States Military Academy included presentations and a discussion of the letter in its annual Senior Conference, whose audience is senior military and civilian defense officials. The Challenge of Peace has also had a longer-term effect in that its way of presenting the idea of just war has been adopted by others, both Catholic and non-Catholic, as what this idea means.

In any case, by the time The Challenge of Peace was published, the recovery of the idea of just war as a focus and resource for moral reflection and debate on the use of armed force was an accomplished fact. The just war idea is now part of the curriculum at all the United States service academies and at the war colleges; in the civilian academic world, it not only has entered the curriculum in such diverse fields as philosophy, political science, and religion but has continued to be treated in academic conferences and in campus lectures; and it has been an element in public debate over the use of armed force in every conflict since the 1980s.

My own place in this recovery of the just war idea has been dual: to seek to identify and recover the historical tradition in its setting and fundamental purpose, and to apply an understanding of just war based in knowledge of that tradition to contemporary issues. These dual aims have produced two different kinds of books: three historical studies, Ideology, Reason, and the Limitation of War,¹⁷

A. Is there a presumption against war or against the use of military force?

That there is such a presumption is, as we have seen, the position taken by the U.S. Catholic bishops in The Challenge of Peace. There it was framed as a “presumption against war” to be found in Catholic teaching but held to be universally binding. In the bishops' 1993 statement The Harvest of Justice Is Sown in Peace, the phrasing was slightly different: “The just-war tradition begins with a strong presumption against the use of force.”²⁵

Now, who is right about the place of this “presumption against war” in relation to just war thinking? Fr. Bryan Hehir, who was the principal drafter of the 1983 pastoral letter of the U.S. bishops, writes in a review of my Morality and Contemporary Warfare:

I am happy that Hehir has conceded my point about the primacy of justice, and the absence of a presumption against war, in the authors who classically defined the idea of just war and thus gave a coherent shape to the tradition. For them it was not force as such that was wrong; for force, they believed, could be an instrument of good as well as of evil, depending on how it was used. Hehir's challenge is now directed to this last point, the idea that force can be anything other than an instrument of evil, and his argument is that “the instruments of modern war and the devastation … which has accompanied most contemporary conflicts” provide the reasons for maintaining a presumption against war. That is, war today is inherently too horrible to be a neutral instrument of good or evil. I note that this is the modern-war pacifist argument in a nutshell. It is, however, problematic in several fundamental ways. First, it tars all uses of force with one brush. I do not see the equivalence between the devastation caused by Iraq's 1990 invasion of Kuwait—including its destruction of much of Kuwait City and its intentional setting on fire of Kuwait's oil fields when its forces were forced out—and the destruction caused by the allied forces against Iraq in response to this aggression, up to and including the air strikes against structures in Baghdad and dual-use targets such as communications nodes and the power grid. Nor do I see the equivalence between the ethnic cleansing of Bosnia (and more recently, Kosovo) and the air strikes used with the aim of bringing such warfare against noncombatants to an end. Moreover, the doctrine, training, technology, and actual employment of force by the United States military in both Afghanistan in 2002 and Iraq in 2003 provide a strong indication that the weapons of contemporary warfare are not all inherently grossly destructive, as Hehir wrongly assumes, and that they do not lead necessarily to “the devastation of civilian society.” His description of “the instruments of modern war and the devastation … which has accompanied most contemporary conflicts” fits the model of World War II very well, and it also reflects the concerns about the level of destruction that would arise from superpower nuclear war, the focus of the 1983 pastoral letter. However, it has little to do with the actual face of contemporary war, whether the low-technology warfare of Somalia or Rwanda (or of contemporary terrorism) or the high-technology warfare the United States military now practices. Nor does Hehir's argument make any distinction as to how, by whom, and to what ends armed force is used. Contrary to Hehir's argument and the idea of the “presumption against war,” for just war tradition as a whole the mere existence of military power does not itself stand as an evil, for it remains within the compass of moral decision whether and how to use the power available. That is where the focus of just war thinking traditionally has been, and in my view it is where it should properly remain.

I confess to some puzzlement as to what the “presumption against war” means in practical terms when, as in much recent religiously based language, it stands alongside a vigorous argument in favor of armed intervention in defense of human rights when these are being egregiously violated. To take an example, the U.S. Catholic bishops' 1993 statement The Harvest of Justice Is Sown in Peace includes a citation from Pope John Paul II that “humanitarian intervention [is] obligatory where the survival of populations and entire ethnic groups is seriously compromised” and follows it with the judgment that “military intervention may … be justified to ensure that starving children can be fed or that whole populations will not be slaughtered.”³⁰

B. What constitutes “last resort” in the use of military force?

Disagreement over the meaning of the just war criterion of “last resort” is closely related to the idea of the “presumption against war.” Let me take as an example the debate during 1990–91 on whether to use force against Iraq to expel it from Kuwait and punish its aggression. At that time, much religious opinion, Catholic and mainline Protestant alike, opposed the use of force against Iraq for a variety of reasons, arguing instead for other measures, including economic and diplomatic sanctions, to compel Iraq to withdraw and to set things right. Use of military force against Iraq, it was argued, should not be undertaken until it was clear that all these other measures, including economic and diplomatic sanctions, had had time to work. Opposition to the use of force, accordingly, was put (in part) in terms of the just war requirement that resort to force be a last resort, understood by those opposing the use of force to require that all other measures conceivably available be used and found to fail first. A decade later, by contrast, one no longer heard about how the sanctions should have been given time to work; rather, moral concerns were being loudly voiced over the effects of the existing sanctions on the civilian population of Iraq. If this was a problem a decade later, it was surely a problem in 1991.

In the debate of 2002–03 over whether to use armed force to remove the Saddam Hussein regime, the U.S. Catholic bishops did not appeal to the “last resort” criterion in their formal statement arguing against the use of such force. Others, however, did so, interpreting this criterion as meaning that every other alternative should first have been tried and proven ineffective. A prominent example of such reasoning was that of former president Jimmy Carter in a New York Times op-ed piece that appeared on March 9, 2003.³¹

But the just war criterion of last resort does not mean that everything except military force must first be tried and have failed. Rather, this criterion, like the resort to force itself, has to be interpreted via a judgment as to the proportionality of proposed nonmilitary means—whether they will cause more good than harm—and as to whether they have any reasonable hope of success. That is, last resort is a criterion to be used in analyzing whether force is the most reasonable and proportionate choice, among all the choices available, to bring about the justified end. It is wrong to use the criterion of last resort as a means of postponing indefinitely any resort to military force.

C. What should we say about sovereign authority today?

At the beginning of his question “On War” (Summa Theologica II-II, q. 40, a. 1), Thomas Aquinas (1225–74) lays down that for a war to be just, three things are necessary: sovereign authority, just cause, and a right intention, which for him included both the aim of peace and avoidance of wrong intention, such as the desire to dominate, “implacable animosity,” or lust for personal gain or power. (He drew all of these requisites from Augustine, whom he cited in explaining them. They had been introduced into the canon law tradition in the twelfth century via Gratian, who also drew them from Augustine.) It is very interesting and important that Aquinas began by requiring sovereign authority, and it is especially notable since nearly all present-day accounts of the jus ad bellum begin with the requirement of just cause. There are two fundamental reasons why Aquinas began here. First, for him as for Augustine and Gratian before him (and the whole thrust of classical just war tradition after him), only the person in sovereign authority, and not any private person, has the right to resort to force. Thus, the sovereign has the ultimate responsibility to weigh whether a just cause exists and decide whether to use force to correct any violation of justice that may appear. Second, the sovereign is responsible for the common weal—immediately, the good of the society over which he is sovereign, and less immediately, the good of the larger order of societies. (Aquinas developed more fully the sovereign's responsibilities in his treatise On Princely Government, and to understand more broadly what sovereignty was understood to entail in medieval and early modern thought, one should consult the body of literature on the good ruler right down through Erasmus.) So authority to resort to armed force, for Aquinas, had to be sovereign authority, because of the sovereign's particular responsibility for the common weal of his society and the order of nations as a whole. This is what lay behind Aquinas's use in this connection of Romans 13:4, a biblical passage much cited in medieval just war discourse: “For rulers are not a terror to good conduct, but to bad…. [The ruler] does not bear the sword in vain; he is the servant of God to execute his wrath on the wrongdoer.” What might this imply today?

The first thing to ask is where “sovereign authority” to use force, one of the principal requirements of the just war tradition, lies today. There are three contenders: the United Nations, and in particular the Security Council; regional security alliances; and individual states. In positive international law, individual states, and by extension alliances of states, have the right and authority to resort to force in defense against an armed attack, whether credibly threatened or in progress. Most armed interventions historically have fitted under this rule; this was the international-law justification for the armed response to Iraq after its takeover of Kuwait. Beyond uses of armed force in defense, the United Nations Charter gives the Security Council the responsibility to authorize such force to deal with threats to international peace and security. This allows for Security Council–authorized military actions, including armed interventions, when the Council has determined that a threat to international peace and security exists.³²

Positive international law derives from the Westphalian system of international order, in which the bedrock assumption is the right of territorial sovereignty. On this assumption the ruling authorities of any state were long held to have the right to do whatever they might wish in dealing with their own population, whatever its shape or consequences. It was only in the wake of World War II and the Holocaust that this conception began to be modified and limited by the growth of a new body of positive international law defining human rights and establishing protections based on them. This new level of recognition and protection of human rights provides much of the impetus for humanitarian intervention in the contemporary context. What is not settled either in positive or in customary international law is exactly what authorities have the right to undertake armed interventions for protection of human rights. Is this to be understood by extension of the right of individual states and alliances of states to use force in defense of themselves or of others who ask for help? Or is it to be understood by extension of the Security Council's right to authorize force in cases of threats to international peace and security? Recent history provides examples of all three sorts of actors and both kinds of rationales for humanitarian interventions.

In traditional just war terms, the state is inherently most capable of meeting the moral requirements of the idea of sovereign authority. The United Nations lacks several important attributes of such authority: it is not in fact sovereign, taking its power from the agreement of its constituent states; it is not responsible or accountable to the people of the world, but only to these states; and it lacks command and control mechanisms, so that it cannot direct the use of force responsibly. Regional security alliances such as NATO have a level of authority, in just war terms, somewhere between that of sovereign states and the United Nations. Concern to maintain the moral meaning of authority to use force leads me to caution internationalists that there remains an important place for individual action by properly governed and rightly motivated states. I am dubious of efforts to restrict the authorization of humanitarian interventions or other uses of force to the United Nations alone. Besides the problems with understanding the United Nations as possessing sovereign authority in the just war sense, it is a sad fact that the United Nations (and in particular the Security Council, which according to the Charter is the body that may authorize the use of armed force in response to threats to international peace) is often prevented from taking action by internal politics. Recent examples include the cases of Rwanda and Kosovo, not to mention Iraq in 2002–03. As for uses of armed force by regional alliances, such as the NATO intervention over the conflict in Kosovo (undertaken in the absence of a Security Council mandate, though the Council's approval was given after the action), I think we should regard these essentially as the consensual joining together of individual states in support of a purpose widely recognized in international humanitarian law. Indeed, such consensus is important as a check on the motivation of any such intervention; on this I agree with Bryan Hehir and others.³³

The moral understanding of the concept of sovereign authority is also what gives states, groups of states, and the Security Council the right to override territorially defined sovereignty when the latter is being abused. When do the rights and protections of sovereignty disappear, on this moral analysis? Under either of two conditions: first, when the governing authorities violate the basic human rights of some or all of their people (since the sovereign's authority to rule follows from service to the common weal, sovereignty is lost, in the moral sense, when state power is used to oppress some or all of the people who live under its rule); and second, in the case of rogue states, states that employ their power to menace others (this, I take it, is the moral meaning of the international-law concept of threats to international peace and security). On this understanding, humanitarian intervention and other uses of force against a state or government that has engaged in massive human rights abuses or that threatens other states or the international order as a whole do not violate the sovereign rights of the state or government that is the object of the intervention, because it has already forfeited those rights by its wrongdoing.

Thus far, I have been discussing issues in the current debate that have to do with the justified resort to force: that is, issues relating to the question of the jus ad bellum. Now let me turn briefly to the current state of thinking related to the question of jus in bello, right conduct in employing justified force.

D. The question of discrimination

First, what is the current thinking about what discrimination requires? The baseline of most recent just war thought on this subject has been the formulation of Paul Ramsey: discrimination requires that there be no direct, intentional attacks upon noncombatants, though the rule of double effect allows indirect, unintentional collateral harm to noncombatants from attacks against combatant targets. Michael Walzer, in Just and Unjust Wars, added a further qualification to the meaning of the double effect rule: that the attacker, “aware of the evil [collateral harm], … seeks to minimize it, accepting costs to himself.”³⁴

As to the first of these questions, recent debate has reintroduced the idea that in contemporary war the combatant-noncombatant distinction collapses. I have never found this argument convincing, and I do not think we need to go beyond Ramsey's and Walzer's response to it: that the argument is overblown, and that there are in every conflict some people who would be noncombatants by any reasonable reckoning. There is good historical reason to hold that the problem with modern warfare is not that the combatant-noncombatant distinction blurs or disappears, but that such warfare has often involved the conscious decision to target noncombatants. An example from World War I is provided by the German Navy's deliberate choice to bombard undefended English channel towns in violation of Hague Convention IX of 1907.³⁵

It helps the cause of the combatant-noncombatant distinction that one of the most evil features of many contemporary armed conflicts, as of contemporary terrorism, is that this distinction has in fact been turned on its head, so that it is not just ignored, but noncombatants have been preferentially targeted as a way of prosecuting war. (Think of the Rwanda genocide, the ethnic cleansing in former Yugoslavia, the terrorism in Northern Ireland, Israel, and Sri Lanka, the amputations of limbs of noncombatants in the conflict in Sierra Leone, the deliberate targeting of the World Trade Center towers in the 9/11 attacks, the deliberate endangering of noncombatants as a tactic used by the Fedayeen Saddam in Iraq in 2003, and the similar targeting of civilians by the Iraqi insurgents today.) But it does not help the idea of this distinction that the air war against Serbia over Kosovo trended in its final days toward something increasingly like strategic bombing, which by definition is bombing aimed at the civilian noncombatant society of the enemy, not at his armed forces or his government. The drift toward justifying such targeting is insidious when it occurs, and it needs to be headed off by planners and target selectors before it develops. At the same time, I think it needs to be said clearly that from the perspective of just war tradition (and, indeed, from both Ramsey and Walzer) there is a real moral difference between (1) hitting a legitimate target with collateral noncombatant harm and (2) directly, intentionally hitting the noncombatants. The mere fact that noncombatants suffer from a bombardment, for example, does not mean that the bombardment was unjust, though it may become unjust if disproportionate. Appreciation for this distinction was not always present in the moral debate over nuclear weapons, and it is not always present now.

The second question, though, is how far the attacker must go, morally speaking, in seeking to avoid collateral harm to noncombatants. What degree of risk or cost should the attacker shoulder? Walzer's argument, or something like it, seems to me to lie behind the moral disquiet some critics expressed over the way the Kosovo intervention was carried out: by planes flying high above the range of Serb air defenses, so that the pilots bore essentially no risk. A similar argument might be made regarding the air war over Afghanistan in 2002 or Iraq in 2003, where in both cases the defense against such attack was minimal. What can one say about this argument? I am sympathetic with the thrust of Walzer's argument, but I think it is wrongly used when it is applied in such cases as these. There is no moral responsibility to take risks and incur costs to oneself when it makes no difference in the outcome, or when the difference made would be negative. Whether a contemporary precision-guided missile (PGM) hits the intended target is not affected by how high the pilot is flying, so long as he remains within the required range. Indeed, for some PGMs (for example, JDAM-equipped bombs) it is necessary for the pilot to fly high so that the aiming device has time to acquire the necessary satellite signal. A further, and different, kind of consideration is that bombing with PGMs may be more accurate when there is no threat from air defense, since such damage-limiting factors as time of day, angle of attack, and choice of weapons-delivery platform then become more important. Indeed, in some cases, higher collateral damage may result from a low-flying plane than from a high-flying one. Walzer makes an important moral point, but it must be applied intelligently, taking into account the realities of the kind of warfare in question. The important moral questions, in any case, are the selection of the target and the means used to attack it.

The principle of discrimination imposes a moral requirement to develop and employ weapons capable of close accuracy and thus able to be less destructive in their effect. Contemporary precision-guided munitions are thus a morally important development, since they are inherently more capable of being used discriminately (and their lower yields make them more proportionate in their effects as well). Some critics have charged that the nature of these weapons—their ability to discriminately hit a given target and cause little or no damage beyond it—may lead to their being used more frequently, perhaps capriciously. Certainly in the recent context, where there have been many pressures for humanitarian intervention and for action against rogue states, the availability of cruise missiles, laser-guided bombs, and other precision-guided munitions may suggest a relatively cost-free line of action that circumvents the moral consideration that should be undertaken before any use of force. If this is the case, then the problem is a possible misuse of the jus ad bellum decision, not of the jus in bello discriminateness and proportionality of these weapons themselves.

The weapons themselves, of course, are only part of the story: also needed is the will to use them discriminately and the embodiment of this will in the training given to those who use them, the development of strategies and tactics for their use focused on avoiding harm to noncombatants, and the monitoring of targeting decisions by a team including experts in the application of the requirements of the law and morality regarding noncombatant immunity. In all these respects, the United States military is currently far out front in development of the capacity to fight so as to minimize harm to noncombatants. The role of the moralist in regard to the conduct of war should be to hold that conduct to the standards that these capabilities have made possible.

E. What constitutes disproportionate force?

I have already referred, in the jus ad bellum discussion above, to the argument of modern-war pacifists, also called just-war pacifists, that modern war is inherently disproportionate in the destruction it causes. I have never found this argument convincing. One problem is: disproportionate to what? It is clear that modern warfare as exemplified by the two World Wars was very destructive; but that modern warfare is inherently so remains to be proven. In any case, the only way to measure moral proportionality in the use of force is to compare the destruction caused with the good produced (which also includes the evil averted). In the jus in bello sense, some just war thinkers have in the past interpreted the requirement of proportionality as meaning opposing force with similar force and no more. This seems to have been one reason for moral criticism of the massive force deployed against the Iraqis in Operation Desert Storm and, in the Kosovo intervention, criticism of the air campaign. But opposing force with similar force can lead to more destruction, not less, as each force is bloodied similarly by the other, additional forces are drawn in on both sides, and the conflict drags on and escalates. There is a proportionality argument for the use of overwhelming force, though this is seldom admitted by persons who regard force itself as the central problem. Again, the proper measure of proportionality in just war terms is harm done against good done; calculation of whether a given amount of force is proportionate or disproportionate follows from that.

But this calculation of proportionality also requires us to ask whether a particular means is the best way to a desired end. The air campaign against Serbia did nothing directly to protect the ethnic Albanian Kosovars, and it may, as some have argued, have triggered worse violence against them by the Serb troops and paramilitaries in Kosovo. Admittedly, the air strikes were expected to cause the Serb forces to cease their violence against the Kosovars, and it was bad calculation that this did not happen. It is also the case that ground-force options were very limited. Yet this discrepancy between ends sought and means employed is the sort of thing one should look at when thinking in terms of the just war requirement of proportionality during an armed conflict, rather than the matter of how much destruction, in raw terms, has been created.

The particular problem of attacks against dual-use targets (those which have both civilian and military uses) raises questions of both discrimination and proportionality. Discrimination does not mean that such targets cannot be morally attacked; rather, the rule of double effect implies just the opposite. Nevertheless, considerations of proportionality may limit such targeting or argue against it entirely. Dual-use targets include power grids, communications nodes, critical highways, railroads, bridges, and the like. These can be legitimate military targets in terms of the criterion of discrimination as defined via the rule of double effect. But military forces typically have a range of backups for all these that noncombatant society lacks. Thus, the collateral damage to noncombatants from an attack on a dual-use target may be disproportionately greater than the damage to the combatants. Again, proportionality requires measuring the damage caused against the justified end. Attacks on dual-use targets may sometimes satisfy this calculation, but sometimes they may not. The decision to attack such targets is thus not just a matter of whether discrimination is satisfied; proportionality must be satisfied as well. For whatever reason, the decision was made in Operation Iraqi Freedom, before the use of armed force began, not to target dual-use facilities. I regard this decision as morally very significant. This was a general rule that might be (and was) overruled in specific, limited instances, when the military value of a facility was judged to be sufficient to warrant its destruction. This illustrates the right way, in my judgment, to approach the targeting of dual-use facilities: saying no to such targeting in general, but with the possibility of overriding this general rule if considerations of military value warrant it and if the requirements of discrimination and proportionality can be satisfied.

F. What about the end of peace?

I find it deeply ironic that the U.S. Catholic bishops' 1983 pastoral The Challenge of Peace did not include the end of peace in its listing of the just war criteria. It is the more tragic that most recent just war debate has paid little attention to this, and that, as events have shown, planning for Operation Iraqi Freedom included disproportionately little on the peaceful rebuilding of Iraqi society, compared to the attention given to the military campaign itself. Nor did the U.S. Catholic bishops address this issue in their “Statement on Iraq”—a fact not excused by the context of their being opposed to the use of force in the first place.

Surely the just war tradition regards the purpose of achieving a genuine peace as a necessary element in the decision on whether the resort to force is justified or not. But having such a purpose implies having the will to achieve it and taking the necessary steps, including planning and commitment of resources, to achieve it. Moreover, the just war tradition includes significant resources for helping to understand what such peace means in fact. In the first place, this peace is the result of creating a justly constituted social and political order. Second, the responsibility of establishing such an order and providing for its continuation and protection is among the obligations of sovereign authority—the same sovereign authority that must make the decision to use force in the first place. The rightness or wrongness of the decision to use force is not simply about the use of force itself, so long as it lasts, but a commitment to the purpose of peace at which the use of force should aim. It is an immoral choice simply to declare military victory and depart.

I suggest that we have, in practical terms, learned a great deal about what is needed for the actual establishment of the conditions for social and political peace in societies ravaged by war (and by previous egregious abuses of human rights) through the experiences of Bosnia and Kosovo. These show both how difficult it is, and how long it is likely to take, to create the conditions for genuine peace. Fundamental institutions have to be rebuilt, often from scratch; the infrastructure of civilian life needs to be repaired or rebuilt; and not least the people who have good reason to mistrust one another must be brought to learn how to live cooperatively with one another. It may well be that doing all this is beyond the physical resources of any single nation—even one as wealthy and powerful as the United States—and the cases of Bosnia and Kosovo argue that, in any case, there is much to be said for a genuinely international participation in the effort to rebuild. Diversity in participation in such an effort may lead to a certain level of inefficiency and even chaos, but it also provides a richness that goes beyond what any one nation may be able to provide. Moreover, the cooperation of diverse nations around the achievement of common goals, motivated by common values, provides a powerful model for societies whose populations have been divided by war. Such cooperation also reduces the likelihood that efforts to establish a just social and political order—and therefore a society at peace within itself and with others—will be regarded as “victor's justice.”

What is notably lacking in recent just war debate is a serious commitment to explore what the end of peace may require, both negatively—that is, in terms of the effort to oppose a regime that systematically violates the core meaning of peace, a just social and political order for its people—and positively—that is, in terms of the commitment implied by the decision to use force to correct the first kind of evil.

Let me conclude this discussion of the end of peace with a few remarks on a special topic, that of war crimes. The commission of war crimes is directly a war-conduct (or jus in bello) issue; but the question of war crimes investigations, prosecutions, and punishment has to do with the end of peace, one of the premier jus ad bellum concerns. For a society to punish its own citizens who are guilty of war crimes is an important ideal, an indication of that society's commitment to a just order. Yet in cases in which such national action is unlikely or impossible, international judicial processes offer an alternative. Almost forty years passed between the Nuremberg and Tokyo trials and the present, ongoing war crimes tribunals for Rwanda and former Yugoslavia, but a standing international war crimes court (the International Criminal Court) now exists and the question of war crimes is much in discussion in various contexts today. It has taken a while for this discussion to develop, and it is still developing. For a time, many in the conflict-resolution debate looked approvingly on the Chilean solution for dealing with atrocities during conflict: “lustration,” or identification of the atrocities and perhaps the perpetrators, but the extension of amnesty toward them. The South African Truth and Reconciliation Commission leaned heavily on this model, but the commission's work was paralleled by more traditional legal investigations, prosecutions, and punishment of those who did not participate in the lustration process and receive amnesty. The atrocities of Rwanda and the former Yugoslavia were so severe and widespread that the international community united around the creation of war crimes tribunals to deal with the perpetrators. This may have implicitly dealt a death blow to the idea of lustration, as the effort to bring former Chilean head of state Augusto Pinochet to trial suggests. One argument against war crimes prosecutions, favored by some in the diplomatic and conflict-resolution communities, was that the most important thing in armed conflicts is to achieve a cease-fire, and the threat of war crimes prosecutions tended to prevent this. Think, for example, of the very different treatment given to Yugoslav head of state Slobodan Milosevic at the time of the Dayton Accords³⁶