Just war tradition addresses the morality of the use of force in two parts: when it is right to resort to armed force (the concern of ius ad bellum) and what it is right to do in using such force (the concern of ius in bello). While these two aspects are related, they are also distinct, and the former has priority: if a given resort to force has not been morally justified, then even the most strictly delimited uses are, according to just war tradition, unjust.

The moral requirements of ius in bello are that a use of armed force be discriminate and proportionate. For ius ad bellum, the requirements are that the resort to force (1) have a just cause, (2) be authorized be a competent authority, (3) be motivated by a right intention, and (4) pass four prudential tests: it must (a) be expected to produce a preponderance of good over evil, (b) have a reasonable hope of success, (c) be a last resort, and (d) have peace as its expected outcome. Some commentators include also the requirement that a war be formally declared, but I take this concern to be satisfied by the others. Either way, formal declaration is required, and this serves two necessary purposes: to make public for all to judge the justification of the resort to force, and to serve fair notice to the enemy so he can make amends before being forced to do so.

In listing the ius ad bellum criteria I have distinguished the three requirements of just cause, competent authority, and right intention from the remaining four prudential concerns. This acknowledges the priority historically given those first three in the tradition as well as the internal logic of the tradition itself. Thomas Aquinas’s treatment is typical as well as authoritative. "In order for a war to be just," he writes, "three things are necessary," and he lists sovereign authority, just cause, and right intention.

The idea of just case is thus one of the most fundamental elements in just war tradition. What are the implications of this idea for statecraft today? What sorts of contemporary situations would satisfy the requirement that for resort to armed force to be justified, a just cause must exist?

In what follows I will seek to answer this question by means of three steps. The first step is to identify the meaning given to just cause by the medieval and early modern thinkers who defined just war tradition in its classic form. My focus here will be on "benchmark" figures: the canonist Gratian and the theologian Thomas Aquinas from the Middle Ages, with reference to earlier authorities, and the theologian Vitoria and the jurist Grotius in the reformulation of just war tradition for the modern age.

The second step is to see how the idea of just cause was affected by the experience of modern war, from the latter part of the nineteenth century through the twentieth. Here I will focus on two major carriers of just war tradition during the modern period: international law and Catholic teaching on war.

The third and last step is to assess just cause in its contemporary context. In defining this context I will look at two issues: (1) the difference between typical contemporary uses of military force and the image of "modern war" as a holocaust driven by the venality of states, and (2) the changing relationship between states and the international order exemplified by the United Nations. In assessing the concept of just cause in this modern context I will examine three questions: First, does the emphasis on defense found in both positive international law and recent Catholic teaching adequately render the classic requirement of just cause? Second, does the idea of just cause ever justify preemptive use of force? Third, may protection of ideals, and not just simply of interests, constitute just cause for resort to force?

THE MEDIEVAL AND EARLY MODERN CONSENSUS

In his magisterial compilation of canon law from the middle of the twelfth century, the Italian legal scholar Gratian defined just war by citing two statements from authoritative Christian writers. The first is from Isidore of Seville, writing around the year 600: "A war is just when, by a formal declaration, it is waged in order to regain what has been stolen or to repel the attack of enemies." The second definition is from Augustine, writing approximately a century earlier: "Those wars are customarily called just which have for their end the revenging of injuries, when it is necessary by war to constrain a city or a nation which has not wished to punish an evil action committed by its citizens, or to restore that which has been taken unjustly." Both these definitions have centrally to do with the idea of just cause, and together they set forth three purposes that justify resort to armed force: to regain something wrongly taken, to defend against attack, and to punish evildoing.

Over the next hundred years Gratian’s canonist successors, the Decretists and the Decretalists, neither added to this conception nor subtracted from it; most of their attention went not to just cause by to a debate over how to define the authority necessary to declare a war just. Thomas Aquinas, writing during the last half of the thirteenth century, reflects the long established medieval consensus on the concept of just cause while revealing his dependence on Gratian and, through him, on Augustine. We recall from above that Thomas identified three conditions as necessary for a war to be just: sovereign authority, just cause, and right intention. On just cause he writes:

Second, a just cause is required, namely that those who are attacked, should be attacked because they deserve it on account of some fault. Wherefore Augustine says (QQ. In Heptateuchum, qu. X, Super Josue): A just war is wont to be described as one that avenges wrongs, when a nation or state has to be punished for refusing to make amends for the wrongs inflicted by its subjects, or to restore what has been seized unjustly.

The French commentator Alfred Vanderpol, writing in the immediate aftermath of the First World War, noted the centrality of punishment of evil in this passage and argued from it to a conception of Scholastic just war doctrine in which just cause is reduced to this alone. I think this goes too far as an interpretation of Scholastic doctrine, and it certainly does not reflect the more balanced position of the canonists, who held to the formulation given by Gratian that there are three causes for resort to armed force: not only punishment of evil but also defense against attack and recovery of something wrongly taken. This broader conception was reinforced by the acknowledgement that Roman law had recognized the same three just causes for a iustum bellum. At the same time, Vanderpol’s formulation draws attention to the fact that the medieval world is not our world, and that the justification of resort to force for the cause of punishing evil, largely lost in the modern period, was emphasized there. Medieval writers on just war made widespread use of Romans 13:4 to define the role of the prince: "He is the minister of God to execute his wrath against the evildoer." The prince had the authority to employ the sword, not only defensively by proactively so as to punish evil persons and thereby right injustices.

Vanderpol’s formulation also draws attention to the fact that Thomas’s passage, as well as the citation form Augustine it includes, makes no specific reference to defense as just cause for resort to force. This is another reflection of the difference between medieval and modern sensibilities, a difference especially striking since, as we shall see, a hallmark of authoritative twentieth-century just war thought has been the effort to restrict just cause to defensive second resort to force in face of an attack. Now, as the canonical sources show clearly, the idea of defense against attack was in fact generally understood in the medieval period to constitute just cause for resort to force. But at the same time, that idea was somewhat problematical theologically in the context of a piety that required Christian participants in the use of force not to violate Jesus’ command to turn the other cheek when struck on the one.

Ambrose’s Paradigm

The pacifist wing of early Christianity had argued that this command of Jesus meant Christians could never participate in war, since doing so would violate this command of Jesus. The theological argument that made Christian just war theory possible was developed by Augustine, building on the position of his mentor Ambrose of Milan. Praising the man who defended his country at personal risk, Ambrose distinguished between using force to defend oneself (which was prohibited by Jesus’ words and example) and using force to defend another person (which followed as a requirement of charity). Developing further the idea that charity sometimes requires resort to force against another person, Ambrose provided a paradigmatic example that was well known both by Augustine and by medieval writers on just war: A Christian is journeying alone in a remote area, carrying a weapon to use against animals he might encounter on the way. He instead encounters an armed bandit in the process of attacking another innocent wayfarer to rob him and perhaps wound or kill him. What is the Christian to do?

In his answer Ambrose did not challenge the accepted doctrine that if the itinerant Christian were himself the victim of the attack, he should not defend himself: the Christian "when he meets an armed robber…cannot return his blows, lest in defending his life he should stain his love for his neighbor." But this is a different case: the attack is on a neighbor whom the Christian is commanded to love. For Ambrose, the Christian has a moral duty in charity to defend this innocent neighbor from the attack and may, to do so, use force if necessary, up to and including doing to the assailant what that assailant is capable of doing to the victim. Not providing such defense is itself morally wrong: "He who does not keep harm off a friend, if he can," Ambrose writes, "is as much in fault as he who causes it." At the same time, the Christian should use no more force than necessary to subdue the attacker, for that person too is someone for whom Christ died. Charity thus justifies the resort to force in defense, not in self but of the other; yet at the same time it limits the force that can be used against the evildoer to what is necessary to end the evil. (Augustine’s similar argument is found in On the Freedom of the Will I.5; cf. Paul Ramsey’s development of this line of reasoning.)

Augustine argued from this to permission for Christians to take part in public warfare with the aim of defending their neighbors in the state, but not to use force as private persons. For the medieval heirs of Augustine, this shifted the focus of the debate away from the question of just cause (theological obligation to defend those wrongly attacked, which was consensually accepted) to the question of the authority necessary to authorize such resort to force. Thomas Aquinas exemplifies this way of casting the issue in his use of Augustine to refute an objection against Christians’ resorting to armed force: "to have recourse to the sword (as a private person) by the authority of the sovereign or judge, or (as a public person) through zeal for justice, and by the authority, so to speak, of God, is not to take the sword."

The Medieval Concept Summarized

In the medieval context, then, the theological argument for defense of the neighbor under attack by an aggressor complemented the conception drawn from Roman law through Gratian that defined three just causes for resort to armed force: defense, the retaking of something wrongly taken, and punishment of evil. At the same time, theological and canonical discussions of the obligation of defense focused more on the question of the legitimate authority to resort to armed force. The theologians, like Thomas, were motivated by a concern to deal with the Christian tradition that forbade Christians to "take the sword" in their own defense; the canonists added a second concern: to limit the overall level of violence in the society by emphasizing that only the highest officials had the right to authorize resort to the sword even for just cause.

One of my purposes thus far has been to suggest that medieval concerns about justified warfare were focused quite differently from such concerns in the twentieth century. For much of the present century, as I will discuss in more detail below, there has been an effort to reduce just cause to the case of defense alone. For the medieval thinkers who helped to define the just war idea in its classic form, the emphasis was different. While they saw defense of the neighbor as being at the very basis of the Christian war idea and as a just cause for resort to the sword, what they emphasized was the right and duty of sovereign rulers to authorize resort to force in order to correct violations of justice. Vanderpol summarized the actions of rulers in uses of force to restore a balance that had been disturbed by the action of an evidoer. Evil acts that might be corrected by force did not have to involve force in themselves; they only had to be evil.

Taken in its totality, the medieval concept of just cause had centrally to do with establishing and enforcing a just political and social order, an order that was necessary for the presence of peace. Thus was the developing just war idea related to the three acknowledged goods to politics: order, justice, and peace.

The discussions in the churchly sources were complemented by reflections on Roman law and custom and, increasingly in the late Middle Ages, by a renewed interest in the concept of ius gentium, law of nations. Together these approaches defined a consensus: just cause for resort to armed force is provided when natural justice is disturbed by some act of evildoing. While such a resort to force must be authorized by sovereign authority and must be carried out with right intention, the justified cause itself may be either defending against unjust attack, punishing evil, or retaking something wrongly taken. This consensus constitutes the classic just war idea of just cause.

The Early Modern Thinkers

Two important changes adapted the idea of just cause to the modern period. First, the justifying causes for resort to force became located squarely within natural law and the law of nations (ius gentium), thereby ruling out appeals to religion (or, implicitly, other ideological causes) as justifying resort to war. Second, the recognition developed that in a given conflict both sides might appear to have just cause. Both these changes are marked in the important bridge figures Francisco de Vitoria, writing in the mid-sixteenth century, and Hugo Grotius, writing in the first half of the seventeenth.

The medieval theorists of just war mixed religious and natural law concerns together in their concept of both ius ad bellum and ius in bello. This was understandable and appropriate within a culture that understood itself to be Christian and found it hard to define the line between the temporal and the spiritual. It meant in practical terms, however, that the developing consensus on just war applied only to wars among members of Christendom, not to wars with non-Christians.

The birth of the modern period was marked by two challenges that required rethinking the just war idea in terms accessible to all humankind, that is, in terms of the law of nature. The first of these challenges was the discovery of the New World, which raised, more acutely than the wars against Islamic enemies had done, the problems of the applicability of just war thinking to conflicts involving non-Christians. The second challenge was the division of Christendom into Catholic and Protestant, which brought home the problems of warfare justified by religious claims far more vividly than religious warfare on the fringes of Christendom had been able to do.

Vitoria: Just Cause and the Law of Nature

The context of Vitoria’s thought on just war was the Spanish encounter with the New World, and his immediate opponents were those Spanish Catholic "developers" of the New World who sought to justify making war against the Indians by appealing to their religious difference and the need to convert them to Christianity. To this argument Vitoria replied flatly, "Difference of religion is not a cause of just war." The only just causes—and this is a point to which he returns repeatedly, in different contexts—are those grounded in natural law and therefore knowable through the use of natural reason. Thus the idea of just war, as developed by Vitoria, is not uniquely Christian; it is in principle an idea common to all humankind. This meant for him both that European Christians should observe its requirements in making war against persons from other cultures and, reciprocally, that persons from other cultures could also be held accountable to fight according to just war principles.

What is just cause as provided for in the law of nature? Vitoria’s general answer was that such cause exists whenever there is a fault knowable through natural reason: "[t]here is a single and only just cause for commencing a war, namely, wrong received." In direct line with the tradition of just cause stretching through the medieval theorists back to the Romans, Vitoria recognized three such specific causes: defense, recovery of something wrongly taken, and punishment for wrongdoing. Significantly, in contrast to the medieval tendency to emphasize the prince’s responsibility to use force for the punishment of evil, Vitoria gave special emphasis to defense of the political community as just cause: "the end aim of war is the defence and preservation of the state." Indeed, in one place he defined the state as any political entity that has the power to use force to support its rights in the presence of any of the three recognized just causes. Elsewhere, however, in a passage that both recalls the medieval concern that just resort to force be to combat evil and expresses his deeply modern interest in the proper conduct of just war, Vitoria specifically cited the right to use force to oppose pillage, rape, and killing.

Vitoria worked within the framework of the established just war tradition, making especial use of Thomas Aquinas. Yet he was able to reshape the focus of the tradition in terms of the concerns of the modern era. His conception of just cause was based in natural law, not in a mix of natural law and Christian moral duty; its central paradigm was not the sovereign acting in God’s stead to punish evil (as provided for in Romans 13:4, that favorite proof-text of medieval just war theorists) but rather the state acting to defend and preserve itself and its rights. In Grotius’s just war thought, as we shall see, these same elements are at center state.

Vitoria, and after him Grotius, also brought a new perspective to the question of where just cause lies in a conflict. Medieval just war theory required that just cause be determined and declared by competent authority, and by the end of the thirteenth century there was a consensus that this mean sovereign authority. But given a plurality of sovereigns, there arose the possibility of rival claims to just cause. Common in chivalric disputes, this problem was exemplified by the rival claims of the French and English monarchs in the Hundred Years War. By the time of Vitoria in the mid-sixteenth century, the concept I call "simultaneous ostensible justice" had eroded the self-confident assumption of the medieval just war theorist that the right and wrong sides in a dispute were simple matters to determine. The fundamental concept of just cause remained intact; the nagging problem was that sometimes both sides of a conflict could make plausible claims to just cause.

If, for example, one party used force against another to retake a piece of property judged to be wrongly taken, this party would by one measure have just cause; at the same time, if the attacked party believed it justly owned the property in question, it would have the right to defend itself and seek to punish the attacker. Vitoria wrote of such cases,

There is no inconsistency, indeed, in holding the war to be a just war on both sides, seeing on the one side there is right and on the other side is invincible ignorance….[But] the rights of war which may be invoked against men who are really guilty and lawless differ from those which may be invoked against the innocent and ignorant.

In other words, Vitoria argued that parties to a conflict must justify their resort to force by appeal to the established concept of just cause, but that they may not always be right in doing so; one (or both) may be invincibly ignorant, and no human judge may be able to find the truth between them. Such is "a just war on both sides," and Vitoria knew enough examples, historical and from his own time, to recognize it as a not uncommon problem. His response was to accept this possibility but to use it to raise a new argument for limits on the conduct of war; that us, he put forward a ius in bello response to an insoluble contradiction in the ius ad bellum.

Grotius: Permitting Preemption

Nearly a century later Grotius confronted the same problem and resolved it in essentially the same way. His resolution became normative for modern international law, which has constituted one of the major vehicles for development of just war tradition during the modern period. Grotius’s treatment of simultaneous ostensible justice—wars in which there appears to be just cause on both sides—was brief but significant. So long as the requirements of justice set by natural law and ius gentium are met, when a war has been solemnly declared by both parties, it is clear that they are fighting by mutual consent to resolve a dispute, and in such a case what is most important is that they both observe the ius in bello limits.

What, though, are these requirements of justice established in natural law and the law of nations? Following the inherited tradition, Grotius wrote, "Three justifiable causes for war are generally cited: defense, recovery of property, and punishment." He continued, however, by explicitly including preemption in his conception of defense: "The first just cause of war…is an injury, which even though not actually committed, threatens our persons or our property." Medieval just war thought had defined the prince’s role in using force to be proactive in response to evildoing; Grotius’s shift of focus was to recognize that such evildoing extends to the preparation for armed attack, not simply the attack itself. "The danger [to be defended against] must be immediate, and as it were, at the point of happening," he said. "If my assailant seizes a weapon with an obvious intention of killing me, I admit too that I have a right to prevent the crime."

In arguing explicitly for preemptive uses of force under certain clear conditions, Grotius was developing an implicit argument within just war theory, not introducing an innovation. James Bowman Scott finds in Vitoria also an approval of preemptive defense against attack. In both these early modern theorists, this position reflects the assumption that protection of justice centrally requires protection of the state, an assumption that led to an emphasis on the just cause of defense that is thoroughly modern. By contrast, we have seen that the idea of defense itself posed certain problems in the context of medieval piety. Medieval just war theorists were perfectly willing to justify many resorts to force that would, in a twentieth-century context, be rejected as cases of "first use" of force; yet they did so by appealing to the just causes of punishing evil and recovering things wrongly taken. Grotius built on this by allowing first use of force also in cases where the just cause is defense.

The most obvious feature in Grotius’s argument for allowing the preemptive use of force in cases of just cause is that he undertook to discuss and justify preemption explicitly. Bringing it out into the open required him to confront two other issues: the sort of threat that in fact justifies preemption, and the kind of moral scrutiny that should be applied to it—and indeed, to all the accepted just causes for war. His discussion of preemption gave him the occasion to distinguish justified preemption uses of force from unjustified offensive uses, thus demonstrating his conviction that the focus must be on the justice of a particular resort to force, not on the question of who first takes up arms.

Safeguards Against Abuse

No sooner did Grotius declare the preemptive resort to force to be allowable in defense than he began to erect safeguards against unwarranted offensive uses. "[P]ersons," he wrote, "who regard any sort of fears as a just ground for the precautionary killing of another person are themselves greatly deceived and deceiving to others." Later he limited the resort to preemption still further:

But quite inadmissible is the doctrine proposed by some, that by the law of nations it is right to take up arms in order to weaken a rising power, which, if it grew too strong, might do us harm….[T]hat the bare possibility that violence may be some day turned on us gives us the right to inflict violence on others is a doctrine repugnant to every principle of justice.

In short, to employ preemptive self-defense one must be absolutely certain that the enemy intends to attack. Even in such cases Grotius counseled caution and recommended other efforts to defuse the crisis, for undertaking war is a "horrible" thing.

The final safeguard Grotius provided to prevent justified preemption from degenerating into unjustified attacks based on "any sort of fears" was the requirement that, when a war is begun, its causes be stated publicly so that "the whole human race, as it were, might weigh the justice of them." Thus the right of sovereigns to judge whether they have a just cause to go to war is limited by their being implicitly held to account in a court of "the whole human race."

In summary, Grotius’s treatment of the idea of just cause embodied the established tradition and further developed its implications. He adhered to the three long established ideas of defense, recovery of something wrongly taken, and punishment of evil as the just causes. Like Vitoria, he thought these derived entirely from the law of nature and could therefore be judged by all humankind. Of the three, he emphasized defense. His explicitly raising the possibility of a justified preemptive use of force served several ends. First it drew attention to the importance of defense as a just cause. Second, it gave him a context within which to develop cautions and safeguards against unjustified resort to armed force. Third, it reinforced the principle that the just causes must be declared publicly for all to see and judge, thus imposing a moral restraint on the sovereign’s claim to be the only judge—a concept inherited from the medieval definition of the just war criterion of right authority.

In all these respects, Grotius set the terms for the treatment of just cause (as well as of just war tradition generally) by the theorists of international law who followed him and, ultimately, for the development of the positive law of war.

One consequence of this was not entirely happy. In the modern state system ratified by the Peace of Westphalia, Vitoria’s and Grotius’s focus on defense of the state as just cause became increasingly more formalized into the concept that the sovereign of a state possesses, on its behalf, competénce de guerre, the right to decide when its interests require defending by resort to war. Grotius’s stress on the need to declare publicly the causes of a resort to armed force was similarly formalized and emptied of moral content by later consensus. The result was that wars ostensibly just on both sides at once—just, that is, in that they were authorized by a sovereign possessing competénce de guerre for causes publicly declared—became increasingly the rule, not the exception as acknowledged by Vitoria and Grotius. Thus the idea of just cause, and indeed the ius ad bellum in general, was more and more rendered through legal formalities, rather than through reflection on its moral content. At the same time, another tendency to set in motion by Vitoria was also apparent: an increased emphasis on limiting the conduct of war, the ius in bello.

MODERN WAR AND JUST CAUSE

In the thought of Vitoria and Grotius, just war tradition, including its idea of just cause, was established firmly on the ground of the law of nature. Other theorists, including Locke in England and the French philosophes, were shortly to argue for a conception of human rights also grounded in nature. These two theoretical developments came together in the two great revolutions of the end of the eighteenth century, the American and the French. The result, while it falls outside the development of just war tradition proper, did have an influence on this evolving tradition.

The difference these revolutions made to the developing concept of ius ad bellum was substantial in two areas. The first was the idea of the necessary authority to resort to armed force. Just war tradition had uniformly required the authority of a sovereign person or body. But by this, revolution was inherently unjust, since the requisite authority was lacking. The American and French revolutions challenged this conservatism in the name of the authority of the individual, who, possessing certain inalienable rights conferred by nature could enter into a collective defense of those rights even against sovereign authority. More significant for our purposes here is the second development set in motion by these two revolutions: a kind of messianism whereby those who had established the right to govern themselves believed they possessed the right to expand this cause. In the aftermath of the French Revolution, the result was a new conception of just cause for war: exporting the Revolution. More broadly, the result was a new doctrine of national war, war justified by an appeal to the defining ideology of the nation and drawing on the resources of the nation’s citizenry as a whole. Thus was modern war begun.

Furthermore, in the post-Revolutionary French conception, offensive warfare, not merely defense, was justifiable by appeal to the ideology of the rights of man. The cautions set in place by Grotius to prevent resort to war because of private fears were swept aside by Napoleon’s efforts to establish all around France nations brought under French control, in the name of the Revolution. This went far beyond the concept of preemptive defense against a real and imminent threat and did much to undermine the case for preemption within the framework of just cause.

From this new conception of just cause for war came two contradictory lines of development. One was the Marxist-Leninist "war of national liberation," which is beyond the scope of this essay. The other, which occurred variously within international law, church doctrine, and philosophical theory, took the form of efforts to set new, more restrictive limits on just cause, or event to deny outright the possibility that such cause might exist. In the following section I will explore two of the most important examples of this trend, positive international law and Catholic teaching on war.

International Law and Just Cause

During the nineteenth century, the trends set in motion by the French Revolution changed the face of war. Increasingly, war became a vehicle for nationalistic aspirations, while at the same time technology made it more destructive and the use of the resources of the whole nation exposed more and more people to its effects. The effort to hold these trends in check concentrated on restricting the incidence of war. It built on the emphasis given to defense of the state as just cause by Vitoria and Grotius at the dawn of the modern period, but drew out this emphasis so that defense became the only justification for resort to armed force. From the perspective of those who saw war itself as the evil to be avoided, the other classically recognized just causes—recovery of something wrongly taken and punishment of evil—were too easily made instruments of national self-interest. Appeal to these other causes also tended to produce wars in which both sides could claim to be fighting justly—a situation far easier to tolerate in the limited "sovereigns' wars" of the eighteenth century than in the rationalistically inspired, totalistic, and far more destructive warfare of the nineteenth. There were, of course, important efforts to limit the destructive impact of war: leading examples of this approach include the Instructions for the Government of Armies of the United States in the Field (General Orders No. 100 of 1863), the Geneva Conventions, the Oxford Manual of 1880, and the actions of the Hague Conferences of 1899 and 1907. In the arena of limiting the resort to war, though, those who wanted to maintain the state system centered their efforts on restricting the resort to force to the case of defense. This effectively ignored the concern of earlier just war tradition—from Gratian through Grotius—that focused on violations of justice as the problem for just war. By the new measure, war itself was the problem.

The limitation of just cause for war to defense alone was attractive to two very different constituencies. From the point of view of those who wanted to limit the incidence of war, it took away the right to wage offensive war for the sake of self-defined national interest, while from the point of view of the states and their political leadership, it supported maintenance of the status quo against potential rivals. This odd confluence of positions masked an irony: by in effect ratifying the status quo of existing states, it served their most fundamental national interest, self-preservation.

In the law of nations, the first steps toward limiting resort to war to defense against attack took the form of major treaties in which groups of nations pledged to support one another defensively if they were attacked (e.g., the Three Emperors' Leagues of 1873 and 1881 and later the Triple Alliance and the Triple Entente). When this approach broke down, however, as in the Crimean War and World War I, the results were the more destructive because the ensuing wars involved alliances of nations, not individual states.

Closing the Door to Preemption

The restriction of just cause for war to defense effectively closed the door on the openness to preemption found in Grotius. Preemption, despite Grotius's cautions and restraints, became identified with aggression. Indeed, aggression itself became identified with firing the first shot, a far less complex condition than what historical just war discussions had recognized as the nature of fault that could justify an armed response.

Article 51 of the United Nations Charter affirms "the inherent right of individual or collective self-defense if an armed attack occurs" against a UN. member, until such time as the Security Council takes steps to deal with the breach of peace. Morton Kaplan and Nicholas Katzenbach comment about this, "[T]he restrictive term 'armed attack' was used deliberately and most commentators would read the Article to forbid self-defense except in case of armed attack." French commentator Henri Meyrowitz has sharply criticized this language of the Charter, arguing that it has removed justice from the ius ad bellum by outlawing first use of force for whatever reason while permitting second, again regardless of circumstances.

If defense is thus equated with second use of force in response to first use ("armed attack"), then the concept of defense does not include an armed response while an expected attack is still gathering but has not yet been launched. This is the possibility Grotius took into account in allowing preemption. If first use of force is prohibited, then even genuinely preemptive resorts to force are disallowed. Reading the Charter in the context of the Pact of Paris and the League of Nations Covenant suggests that this is what is intended; the goal is to prohibit states from initiating armed violence in a conflict with other states while preserving the right of victims of aggression to defend themselves.

Yet this is not the only possible meaning. Restricting just cause to defense against an armed attack already launched is a problematical doctrine that does not well suit the actual circumstances of many conflicts. Kaplan and Katzenbach note that the wording of the Charter "does not clearly forbid self-defense prior to armed attack but only sanctions self-defense as permissible in case of armed attack." The judgments of states in actual cases have not shown a doctrinaire rejection of first use of force when it is judged genuinely to represent preemption of an attack about to be launched or under way but not yet landed. The United States, for example, accepted the Israeli preemptive strike at the beginning of the Six-Day War of 1967 as justified while disapproving the Indian military move into East Bengal during the war that led to the creation of Bangladesh. There have also been disagreements as to what constitutes "aggression" and what "defense." During the Cold War, the judgment normally depended on which side one was on. A "war of national liberation" was thus defensive in the Soviet view while aggressive from the perspective of the United States.

The effort to reduce just cause for resort to force solely to defense has had another unforeseen result: expansion of the concept of defense to include other categories as well. For example, nuclear deterrence has for decades routinely been characterized as "defense," though it actually rests on a threat of retaliation. Such retaliation would be, to be sure, a second use of force in response to a first strike; yet it is clearly something different from the root meaning of defense as an action or actions taken to prevent an attack from succeeding. A second example is provided by the war between Argentina and Britain over the Falkland Islands, which both sides characterized as "defensive," though both included in this concept the classic just war idea of recovering property wrongly taken. The Gulf War provides a third example. Here the West defined its action against Iraq legally as response to an "armed attack" that was under way though the Iraqi takeover of Kuwait by force was quickly accomplished at the start of the crisis. Legally, the "armed attack" remained in process as long as Iraq continued its military occupation of Kuwait. Any theorist familiar with the concept of recovery of something wrongly taken would not, however, have had to stretch the concept of defense so far to find just cause for the coalition’s armed action against Iraq.

Catholic Just War Thought and Just Cause

Like positive international law, twentieth-century Catholic doctrine has sought to limit resort to force by narrowing the concept of just cause to defense alone. The roots of this approach are in a perception of modern war as a source of injustice rather than a means of fighting injustice. Thus in 1870, five years after the end of the American Civil War and in the same year as the Franco-Prussian War, a statement of several postulata was presented to the first Vatican Council in which the contemporary form of war as practiced by European nations was explicitly challenged as unjust. The document singled out large national standing armies as a special evil, arguing that they fostered a spirit of militarism, tended to foment wars in order to make them "pay for themselves" through conquest, and produced conflicts so destructive as to be "hideous massacres" the Church could not regard as just. So far as the ius ad bellum was concerned, this argument cut against the possibility of a justifiable first use of force, though it admitted the right of second resort to force in defense.

Similarly, in 1931 the Conventus of Fribourg, a gathering of theologians, distinguished between war for "defense," which was "lawful," and war from national "necessity," which was not. In the context of the provisions for arbitration of disputes established by the League of Nations and the renunciation of first use of force established for the signatories to the Pact of Paris, the Conventus took the position that it is wrong to initiate resort to arms to settle a dispute without first recourse to arbitration.

Since World War II, various official and non-official statements have gone a good deal further than this, calling into question whether, given the nature of modern war, even the just cause of defense can legitimize resort to armed force. In what follows I will concentrate on papal statements, which have undeniable authoritative force, though they represent only a fraction of the full range of recent Catholic thought on war.

Characterizing the position of Pius XII, John Courtney Murray wrote that this pope forbade "all wars of aggression, whether just or unjust" (sic!), while finding "morally admissible" "a defensive war to repress injustice." Pius's language revealed his hesitation even about the defensive use of force. In his 1956 Christmas message, reflecting the context of the Hungarian revolution and its repression by Soviet armed force, he wrote:

There is no further room for doubt about the purposes and methods that lie behind tanks when they crash resoundingly across frontiers . . . When all the possible stages of negotiation and mediation are by-passed, and when the threat is made to use atomic arms to obtain concrete demands, whether these are justified or not, it becomes clear that . . . there may come into existence in a nation a situation in which all hope of averting war becomes vain. In this situation a war of efficacious self-defense against unjust attacks, while undertaken with hope of success, cannot be considered illicit.

This is explicit just war language, but it has a very contemporary twist. Medieval and early modern just war theorists focused on the problems of injustice that a use of force by sovereign authority might set right; for Pius, as for the Fribourg theologians in 1931 and the 1870 postulata before that, it is the use of force itself, even to serve just ends, that is problematical and needs to be hedged about with safeguards. The threat to use atomic arms is a new element mentioned by Pius, but the basic shift in the focus within the ius ad bellum came earlier—as early, indeed, as the denunciation of large standing national armies in 1870 and the new emphasis on arbitration in 1931.

Giving his own weight to this new emphasis, in Pacem in Terris (1963) Pope John XXIII called for the banning of nuclear weapons, a general reduction of other arms, and the development of an international regime based on common consent that would be able to resolve disputes without resort to war. In a widely discussed passage he wrote, "[I]n this age which boasts of its atomic power, it no longer makes sense to maintain that war is a fit instrument with which to repair the violation of justice" (paragraph 127). Catholic modern-war pacifists argued that this statement not only condemned all war in the nuclear age but rejected just war theory as well. By contrast, Paul Ramsey reasoned that John XXIII instead was working within the just war framework, ruling out only two of the three classical just causes, recovery of something wrongly taken and punishment of evil, while leaving defense as justified. While I side with Ramsey’s interpretation, I believe more attention has to be paid to what was given up here. To "repair the violation of justice," after all, was precisely what classic just war doctrine was about.

The "Presumption Against War"

By this point in the development of recent Catholic thought on just war it is clear that the focus has shifted to a concern that the resort to force, for whatever reason, itself holds great potential for injustice, and that this must be avoided. At the same time, defensive resort to arms remains a moral possibility, though an increasingly questioned one.

In Pope Paul VI’s 1965 address to the United Nations General Assembly, this tortured line of reasoning reached for a new resolution. While issuing the ringing challenge "[n]ever again war, war never again!" Paul also admitted that so long as man remains "weak, changeable, and wicked," "defensive arms will, alas! be necessary." But he stopped short of explicitly saying that it is morally allowable to use such arms; his point was rather to draw a distinction between the possession of offensive arms, which he regarded as morally evil, and the possession of defensive ones, which he permitted because of the current "weak, changeable, and wicked" state of humanity.

The concept that just war doctrine begins with a "presumption against war," which appears in the 1984 pastoral of the American Catholic bishops, reflects the shift in focus illustrated by the examples above. It is important to recognize that this is a change of major dimensions in just war theory. To put the matter plainly, this attitude toward armed force is not the problem that classic medieval and early modern Christian just war theory sought to deal with; that problem was injustice, and force (under the conditions established by the just war idea) provided the means to deal with it. The concept that force itself is a major problem originated only comparatively recently as a result of the encounter with modern war, judged as an enterprise whose great destructive potential will inevitably be realized once resort to arms has been allowed.

J. Brian Hehir traces the development of the "presumption against war" as also characteristic of the position of John Paul II. Citing a letter from this pope to President George Bush, Hehir remarks (in language reminiscent of John Courtney Murray's comment on Pius XII) that while John Paul's use of just war logic is "clearly evident," his conclusion is that "resort to force is not justified even though a just cause exists."

The base line of post-World War II Catholic thought on just cause for war has, in general, formally paralleled the position defined in positive international law by the United Nations Charter, that only defense against attack provides just cause for resort to force. Catholic thought, however, actually diverges from this formal similarity by imposing a further significant restriction: even when such just cause is present, the more moral course may nonetheless be not to resort to force. The weight of argument here has shifted away from the classic emphasis on the requirements of just cause, right authority, and right intention to the prudential considerations of overall proportionality, last resort, and reasonable hope of success. For recent official Catholic teaching, these have the power to overrule the presence of a recognized just cause.

Going still further than the papal statements we have reviewed, Brian Hehir regards as indicative of the trend of official Vatican doctrine an editorial severely critical of the Gulf War published in the influential Roman journal Civiltà Cattolica in 1991. According to this editorial, Hehir writes, modern war is inevitably unjust, with only one limited exception: "the single exception of a war of pure defense against an aggressor actually taking place." There is a significant difference between the meaning of an aggression "actually taking place" in this passage and the meaning found in international law, as applied to Iraq's military occupation of Kuwait. While Catholic thought earlier in this century tended to reflect the state of positive international law, this editorial takes a considerably more restrictive position on the allowability of resort to force.

The underlying reason for this fundamental shift in the structure of the moral argument is a judgment about the nature of modern war as disproportionately destructive and itself the source of great injustice. This conception has repeatedly surfaced in the sources cited above representing official and near-official Catholic thought on war from the time of the first Vatican Council to the present. For the 1870 postulata, the threat to be avoided was that of large standing national armies and the militarism they inculcated, together with the destructiveness such armies entailed in wartime. For the 1931 Conventus of Fribourg, the same threat lurks in the background, magnified by the memory of the Great War, and arbitration is held up as an alternative to war for the future.

By the time of Pius XII the threat has taken the even more ominous shape of the destructive power of atomic weapons, and it is this theme to which subsequent popes return repeatedly in their own statements about the right to resort to war. While defense continues to be somewhat reluctantly permitted, even this is undercut by the position Murray and Hehir find in Pius XII and John Paul II: that resort to armed force may not be justified even when such a just cause exists. In such a position, the idea of just cause has dwindled to little more than a formal placeholder, and the heavy lifting of deciding whether to resort to force in the service of statecraft has been given over to prudential calculations in which the conditions are tilted against any possibility that force can serve the cause of justice.

This position represents an enormous turnaround relative to classic medieval and early modern just war doctrine. Where has it left us with regard to the idea of just cause?

WHY JUST CAUSE NEEDS REASSESSMENT

There are, in my view, two important reasons why the concept of just cause needs to be reassessed in the current environment. The first is the moral inadequacy of the idea of just cause in its current state in positive international law and its even more woeful state in recent Catholic teaching. The second is that these authoritative contemporary statements of the idea of just cause are founded on an understanding of the international order, the nation-state, and the nature of war that rests on outmoded assumptions.

As we have seen, just war theory in its classic medieval and early modern form defined a place for the moral use of armed force by politically sovereign communities. In the context of this theory, armed force was itself morally neutral; it might be employed for good or ill, according to the context. What just war theory sought to do was to specify the conditions required for the use of force to serve justice.

"In order for a war to be just," as Thomas Aquinas put the matter in stark simplicity, "three things are necessary." First, sovereignty—having no earthly superior, according to the medieval writers; also having the ability to defend the rights of one's own political community, according to the addition made by Vitoria—defined whose authority it was necessary to have before such force could be used. The second necessity was just cause, which in the classic theory included three justifying rationales for resort to armed force: defense against attack, recovery of something wrongly taken, and the punishment of wrongdoing. It was the responsibility of the sovereign authority to determine whether, in a given case, one or more of these justifying rationales was present. The third necessary condition was that the decision should be undertaken with right intention, which was understood positively to be an intent in line with just cause, and negatively to be the avoidance of various kinds of evil motivations. These latter were defined in a passage from Augustine that set the standard: "the desire for harming, the cruelty of avenging, an unruly and implacable animosity, the rage of rebellion, the lust of domination and the like—these are the things to be blamed in war." The sovereign authority's decision regarding resort to force was also to be guided by other prudential concerns, but just war theory in its classic form did not dwell on these; what was necessary for a justified resort to force was the set of three conditions cited by Thomas: sovereign authority, just cause, and right intention.

I have shown how twentieth-century positive international law has sought to restrict the resort to force to the case of defense against aggression, with offensive resort to force denied as a means for resolving inter-state disputes. Under the controverted first-use/second-use distinction, aggression is defined as first use of force regardless of circumstances, while defense becomes second use alone. The classic just war conception of just cause is more comprehensive in the possibilities it anticipates. Defense there includes the possibility of genuine preemption of an attack (subject to the conditions for right intention), as Grotius’s discussion makes plain, and it also allows resort to force to recover something wrongly taken and to punish wrongdoing. As I have argued above, in the contemporary usage of states the concept of defense has tended to expand to include uses of force for such reasons, evidence that there remain justifying reasons for the use of force beyond that of defensive response to an armed attack in progress. In effect, the concept of just cause explicitly stated in classic just war theory has come into contemporary international law implicitly, through the back door.

The United Nations Charter, in Chapter 7, reserves to the Security Council certain additional justifications for interventionary uses of force, notably peacekeeping and response to threats to international peace and security. These latter threats are not limited to cases of aggression, and in any case the United Nations is not bound by the "no first use" rule in the face of such threats. So it is possible to argue that so far as this international body is concerned, despite the legal effort to restrict states from employing armed force except in defense against "armed attack," the concept of just cause defined in classic just war theory remains honored.

By its very nature, law cannot render the fine details of moral argument. Its purpose also is different and more narrowly focused: it is a hedge against undesirable behavior. Nonetheless, law bears an important relation to moral concerns, and over time these concerns may emerge in greater fullness through the interpretations attached to the positive law and the behaviors aimed at complying with it.

The roots of international law on war are in the just war tradition, and international law is, in historical perspective, one of the most important carriers of that tradition during the modern period. The effort to limit just cause for resort to force to cases of defense against attack puts into positive-law form only a portion of the idea of just cause inherited from the larger tradition. That restricting effort came into being in a particular context in which the other traditional elements of just cause were understood as being addressed at the level of the international order. The resurgence of those other elements in an expanded concept of defense reflects the failure of the international means that were intended to address them. The question now is how to draw out the whole range of elements recognized in the classic theory so as to clarify their present-day implications for policy and political decision-making. I will return to this in the following section.

Relative to the moral content of the classical theory of just war, the contemporary state of Catholic thought on war is, in my judgment, far more problematical than is international law. For in recent authoritative Catholic teaching, not only has just cause for resort to force by a state been reduced to a defensive response to an attack still in progress (as in positive international law), but even that allowance has been undercut by two innovations in interpreting just war tradition.

The first innovation is identifying the resort to force as itself morally questionable. This is the development that the 1983 statement of the American Catholic bishops terms the "presumption against war." This "presumption" reflects judgments about the nature of war and the motives of states that can be traced to the era of Vatican Council I and that intensified with the development of nuclear weapons.

The second innovation in recent Catholic thought on war is that the ius ad bellum priority is given to the place of contingent prudential judgments (namely, the amount of destruction that can be anticipated, whether the situation is genuinely one of last resort, whether there is a reasonable hope of success), so that resort to force is effectively questioned or denied even when there is admitted just cause. This entirely inverts the logic of the classic theorists and goes far toward removing force from the tools of statecraft employable in the service of justice.

I will argue below that the justification for these prudential judgments is both one-sided and outmoded in the present context, but my point here is a different one: that this inversion of the logic of the ius ad bellum represents a deep unfaithfulness to the values expressed in classic just war thought. The classic theorists, among whom those discussed above are benchmark figures, did not approach the question of war with a presumption against the use of armed force; what motivated them was a presumption against injustice. The fundamental rationale was to prevent injustice even at risk to oneself, as shown by the paradigm from Ambrose about the Christian encountering an armed bandit who was attacking an innocent traveler. That need to prevent injustice was what defined the role of the prince as "minister of God" in the often cited text from Romans 13 (the ruler "is the minister of God, a revenger to execute wrath" upon the evildoer) that figures centrally in Thomas Aquinas's comments on the justification of war.

The problem with prudential judgments is not that they are prudential but that they are contingent. For this reason, classic medieval and early modern just war theory placed the responsibility for the prudential concerns included in the ius ad bellum on the competent authority who determines whether to resort to armed force. In other words, these concerns pertain to the function of statecraft; the role of the moralist is to specify that they must be taken into account, not to usurp the role of statecraft by specifying how they are to apply, or what they mean for specific instances or general periods of time.

In contemporary Catholic thought on the ius ad bellum, the assumption on which the analysis depends is the "presumption against war," the assumption that, in the present age, war may no longer be employed to remedy "violations of justice." But it was precisely "violations of justice" that the classic just war theorists aimed to address and remedy. In these two contexts, the prudential concerns of overall proportionality, last resort, and reasonable hope of success take on different colorations. There is no doubt that the classic just war theorists were concerned to right injustices. By comparison, the logic of recent Catholic teaching on war seems to leave no doubt that the intent is to avoid resort to force. This is, I suggest, a cause for concern, unless it is granted in advance that such resort always produces the greatest injustice. I have already shown the link between the development of the idea of the "presumption against war" and the judgments made by critical actors about the nature and motivations of war as they understood them. The question is whether the uses of military force typical of the present day justify such judgments.

On the basis of the experience of the two world wars and, before that, "national war" as defined in the nineteenth century, positive international law on the resort to war defined its concept of just cause in terms of assumptions about nations, conflict among nations, and the hope of an international order in which such conflict would gradually be eliminated. The understanding of war shaped by this experience was of a totalistic form of conflict in which winning or losing came to have cosmic implications.

At the same time, the victorious powers who brought the United Nations into being, and who assigned themselves permanent places on the Security Council, did not for a minute doubt that the use of military means in a just cause has a central and necessary role in international politics. Accordingly, states were not to avail themselves of military means in an effort to serve their interests in a dispute unless the other party did so first (unlawfully). Here the principal villain is represented to be not the destructiveness of war itself but rather the evil of aggression, defined as first resort to force in the settlement of a dispute between nations. Pointedly, the United Nations Charter reserves the right for the Security Council to authorize resort to force for unspecified threats to international peace and security. Twentieth-century international law thus maintains an understanding of war as a potential instrument for purposeful human activity against injustice, in which both states and the international community have a role.

By contrast, recent Catholic thought has been deeply marked by an understanding of modern war as itself so morally questionable that the ability of human purpose to shape it and use it to serve justice has been all but lost: what remains is the ability to seek to prevent it. As we have seen, two themes stand out: first, that the moral possibility of national purpose has been subverted by the militarism imposed by large military establishments, for which the only cure is disarmament; and second, that the destructiveness of modern weapons, and in particular nuclear weapons, severely restricts and perhaps eliminates the possibility of resort to them as instruments of moral purpose. Neither of these themes holds up as a general descriptive statement either of the nature of contemporary states and statecraft or of the actuality of war once begun. Both are seriously outmoded in the post-Cold War context.

In the first place, the nature of the actual wars that have occurred since the end of the Cold War stands out, not as something whose destructiveness is inexorably beyond human control and whose point far outruns the ends of politics, but as something deeply shaped by human decision-making and expressive of political purpose. These conflicts have been limited ones in different but significant ways; none has ushered in a global holocaust, and none has escalated to all-out use of the military might of the great powers, including nuclear weapons. Nor, indeed, is this only a recent phenomenon. In truth, the face of armed conflict since the end of World War II has been essentially the same as in these post-Cold War conflicts.

This suggests that "modern war" is now this: localized, limited though sharp conflicts in which ethnic or religious differences or local political disputes provide the proximate causes, not totalistic clashes on the model of the two world wars or the feared global nuclear holocaust. The reality of such conflicts has, indeed, been terrible enough; yet the rape of Kuwait, the starvation of civilians in Somalia, and the ethnic massacres in Rwanda and the former Yugoslavia have not exemplified a type of destructiveness different from what was known by Vitoria, Grotius, or their predecessors. (Grotius, after all, lived during the Thirty Years War, arguably the most devastating conflict Europe has ever experienced.) All these conflicts have been condemned by the international community, and each has occasioned action by members of that community to relieve suffering and end the conflict. In these responses, military means belonging to the great powers have been brought to bear in limited rather than totalistic ways, and with varying degrees of success.

This is remarkable in two important respects. The first is that these cases have defined the limits of what various forms of the international community can do. The United Nations has had success at peacekeeping, but other international coalitions have been necessary where peace does not exist or exists only tenuously, as in the cases of the Gulf War and the NATO intervention in Bosnia. The second remarkable element in the way the major powers have employed their military forces in these conflicts is that in doing so they have gone substantially beyond a narrow definition of their national interests to include humanitarian and international-order concerns—just the opposite of what they were expected to do on the model of the state that emphasizes militarism, national chauvinism, and venality.

JUST CAUSE REASSESSESSED: IMPLICATIONS FOR MORAL STATECRAFT

It is apparent that the concept of just cause for resort to force is undergoing significant reinterpretation in the framework of statecraft; but moral doctrine has not yet examined what this implies for just cause in the framework of just war tradition. I turn to this problem in what follows.

While classic just war theory envisioned the state, under the authority of its sovereign head, as the central actor in the decision whether to employ force to combat injustice, twentieth-century legal and moral thought in the just war tradition has sought to limit the right of individual states to resort to force while reserving a larger latitude to international organizations. For the United Nations Charter and for much moral reflection hostile to the state as well, the latter meant one organization in particular: the United Nations. The right to engage in offensive uses of force, in the sense of military actions across borders, was located here, while other groupings of states, whether formal treaty alliances like NATO and the Warsaw Pact or ad hoc coalitions like that formed in response to Iraq's invasion of Kuwait, were held to the same restrictions as individual states: legitimate resort to armed force only for the purpose of defense.

Moral thought shaped by visions of the militarism, self-interestedness, and venality of states, not to mention internationalists focused on the United Nations as the beginning of a new world order, neglected to take adequate account of a fundamental fact: that real power was not located there but remained with the individual states and in groupings of states for a common purpose. In this sense these efforts to define a form of statecraft in which states play a subordinate role were Utopian, imagining a reality that did not exist and degrading the reality that did exist. The relentlessly negative portrayal of the state as an institution both disregarded the positive attributes of the state system and ignored differences in the way specific states were constituted and behaved.

The uncritically positive attitude toward the possibilities of international order, on the other hand, overlooked the fact that the structure of order defined through the United Nations could not stand alone; rather, it depended on viable states in order to function. Further, this attitude toward the United Nations did not take account of the fact that under the conditions of the Cold War, this organization was not able to do even the best it was capable of in living up to the role envisioned for it in the Charter. The end of the Cold War set the United Nations free to act in accord with what the Charter provided: to intervene in conflicts where no peace had been established in order to set right conditions that posed a threat to international peace and security.

Yet paradoxically, its newly achieved freedom to act in this way showed clearly that the United Nations lacks the attributes it needs to do so effectively. It lacks cohesion, so that policies and decisions have led to inconstancy on the ground of the conflicts it has addressed. It lacks sovereignty in the sense that Vitoria singled out, the power to assert and defend its own rights. It lacks an effective chain of command for military forces set in the midst of an ongoing conflict, which means that these forces cannot be an effective arm of international statecraft. These qualities are in fact necessary characteristics of the state as a political institution, and their absence at once shows the limits of the United Nations and the continuing importance of states in the international system. All the deficiencies mentioned are in the first place defects in sovereign authority, but since without such authority there is no entity competent to determine just cause and undertake military action on its behalf, the lack of these qualities undermines the positive-law definition of just cause in which certain rights regarding the use of force are reserved to the Security Council while being denied to states or other groupings of states. In the practical arena, the fiascos in Bosnia and, earlier, in Somalia have brought these problems to light.

At the same time, the press of events has produced a nascent customary law that preserves the form of extant positive international law while reflecting the continuing rights and responsibilities of states. The customary law proceeds from the fact that viable states possess what the United Nations does not: competent authority to formulate policies and reach decisions regarding the just use of force, to exercise command over such force, and to make assessments of their rights and responsibilities relative to ongoing conflicts even when they have not been party to these conflicts.

Many commentators regard customary international law, based on the collective attitudes and actions of states, as the real international law, rather than that which is written down in positive form, unless the latter is backed up by state attitudes and behavior. So it is especially important, I think, that the crises in Kuwait, Somalia, and the former Yugoslavia have brought into being a process by which the rights of just cause reserved to the United Nations in positive international law have been extended over individual states and coalitions of states, to give them rights to use military force across national borders that the positive-law concept of just cause sought to deny them. These three cases exemplify this extension in different ways. The legal grounding of the response to the invasion and occupation of Kuwait, where the extension first appears, was admittedly mixed. While the coalition's action was carefully defined so as to fit the conditions of Article 51 of the Charter, whereby groups of states are given the right collectively to respond to an ongoing armed attack, Security Council authority—not strictly required under the terms of Article 51—was also sought and obtained for action. Somalia too provides a mixed lesson: the United States and other individual nations contributed forces under the legal authority of the United Nations and in accord with its definition of just cause; yet in the case of the U.S. forces, the chain of command was American, and the United Nations had only an ineffective command authority over the other national forces present. The problem of an effective chain of command carried over into Bosnia, both while the intervention was entirely a U.N. operation and after it became a mixed U.N.-NATO cooperative effort. However, the state of affairs achieved in Bosnia after the Dayton accords carries the development I have described to what may be a new state of equilibrium, in which regional alliances employ interventionary force with the formal authorization of the United Nations and in accord with the just causes reserved to that body, causes going beyond what is allowed such regional alliances by positive international law.

Now, while I have had a good deal to say about the question of authority, these reflections bear simultaneously on the question of just cause, since these two elements of the ius ad bellum are closely intertwined. Encapsulated within the development I have sketched is a significant expansion of the de facto conception of just cause for leading states and powerful groupings of states able to shape Security Council decisions. Whatever the de jure limits on the right of a state or a group of states to engage in the use of force across national boundaries, if Security Council sanction for such action can be obtained, the result is effectively the same as if the states directly possessed that right. This possibility has existed since 1945, but during the Cold War it was limited by the presence of the veto in the Security Council. Now, the logjam of a party-line veto has given way to a situation in which, in practical terms, what is required is that the majority of Security Council members agree to support a particular use of force, while no one permanent member opposes it enough to veto it. This implies that the extension of the just cause idea I have described will take place only with coalitions of nations whose core includes a majority of the permanent Security Council members.

It is notable that both NATO and the coalition formed against Iraq in the Gulf War satisfy this condition. While the latter was an ad hoc grouping of nations for a single purpose, NATO's ongoing institutional existence defined by treaty, common interests of the members, and a half-century history of cooperation gives it a much more significant potential role. NATO was brought into existence in accord with the understanding set out in the United Nations Charter that regional alliances of states could be formed for a defensive purpose. It was thus defined formally by the same highly restricted positive-law conception of just-cause-for-use-of-armed-force that applied to individual states.

The debate over NATO involvement in Bosnia and the gradual growth of that involvement marks a transition away from this conception of NATO's role, and it also marks the coalescence of a new definition of just cause for the use of forces under NATO command. With the replacement of the U.N. peacekeeping forces by a robust NATO force, and with tactical decisions regarding just cause for use of that force in the hands of the NATO chain of command, a state of affairs has been reached that embodies the new conception I have sketched above. The positive legal authority for this force's presence remains that defined by the framework of the U.N. Charter; but the de facto authority for the use of force has been delegated to this regional organization, which has been given the power to act within the broader framework of just cause that was earlier denied to it—a framework that includes not only defense of self but also defense of the rights of others.

This development is extremely significant in both political and moral terms: politically, in that it embodies a conception of a political unit greater than the individual state, yet not so Utopian as earlier conceptions of world order; morally, in that it embodies both (a) the recognition of a concept of just cause for use of military force that goes beyond the narrow right of self-defense and (b) the extension of this concept to a regional grouping of states.

The United States, because of its post-Cold War preeminence, is positioned to be considerably affected—with both benefits and burdens—by this de facto redistribution of the right to resort to force for reasons other than national defense against armed attack. At the same time, the nature of the shift implicitly requires that such decisions be subject to the approval of the other powers that make up the permanent membership of the Security Council and participate in such regional security groupings as NATO or ad hoc coalitions that may be formed in response to particular crises. This suggests that the states involved in such groupings must share more than simply common interests: they must agree that common values are at stake. Thus there seems to me to be a tilt here toward support for broadly recognized rights and humanitarian needs, a point to which I will return below.

The Possibility of Preemption

What this developing de facto state of affairs implies for major powers acting in their own spheres of interest, either unilaterally or at the head of regional groupings of states, also seems clear by this point. Whether it is the United States employing military force in the Western Hemisphere (as in Grenada, Panama, and Haiti), or Russia in the Caucasus (as in Chechnya and, more limitedly, elsewhere), or France in its former colonies in central Africa, the restrictive limits of the de jure definition of just cause no longer apply—if, indeed, they ever in reality had the force they claimed.

All this bears directly on the possibility for genuinely preemptive uses of force in which there are actions across a national border in response to perceived security threats while those threats are developing, or, more broadly, in response to violations of human rights or other prominent evils that the local authorities either do not address or are unable to deal with. The behavior of states since 1945 has never consistently ratified the effort in Article 2 of the U.N. Charter to disallow cross-border projections of force except after a first military attack has fallen.

Yet there are two new elements in the current scene: first, the recognition that the danger may not be military but may nonetheless threaten national security (e.g., the drug trade, terrorism and other forms of hostile acts by the leadership of a foreign country or with their approval and support); second, the possibility of interventions to correct ills that are not themselves directly or immediately threatening to national security but are major violations of universal values that the local government cannot or has not sought to remedy (indeed, it may itself be the source of the violations). The U.S. intervention in Haiti exemplifies a national action to set right violations of values that had both these characteristics at the same time.

These last considerations introduce another morally significant element in the developing de facto understanding of just cause for use of armed force: that just cause as currently understood in practice may proceed either from concerns of national interest that include but go beyond immediate military threats, or from concern to protect universal values, remedy their violation, and prevent continuing violations. At the same time, the use of military force that is justified in these ways is not the same as that envisioned in the effort to restrict military action to responses to armed attack. This latter conception envisioned military action as the initiation of war between nations, war that might escalate to become total in its means and draw other nations into it so that it became global. While the redefined just cause I have been describing includes this as an extreme possibility, it chiefly has to do with far more restrained and local applications of military force.

Indeed, such applications may be not to make war at all but to encourage the establishment of peace: to separate warring parties, to provide or facilitate delivery of food or medical care, to keep peace while a fractured society rebuilds, and possibly to support such rebuilding not only morally but materially. Above this level but still well below the level of all-out war are uses of military means that might involve interdiction or punishment of organized criminal activities (e.g., U.S. use of air, naval, and military intelligence capabilities against the Latin American drug trade), limited applications of force to discourage and punish aggression (e.g., the use of NATO air and U.N. artillery strikes in Bosnia in the period prior to the signing of the peace accord), or protection of the rights of minorities (e.g., enforcement of the protective zones designed to benefit the Shiite and Kurdish populations in Iraq). Also at this intermediate level are military responses to terrorist activity (e.g., Israel’s ongoing military action in southern Lebanon, the U.S. air strike against Libya) and preemptive limited military strikes to remove a threat still in the process of developing (e.g., Israel’s use of air power against an Iraqi nuclear reactor capable of producing weapons-grade fissionable material).

Where, in the above mixture of situations, do interests end and ideals begin? I suggest that in the present environment, interests and ideals are not discrete alternatives but mutually supplemental sources for the idea of justice in just cause for resort to armed force, as exemplified by the variety of causes being served in the above cases. Indeed, I would carry this argument further. If the paradigm is that individual states and regional organizations of states may resort to force only in armed self-defense against attack by other armed force, then the argument from national or regional security interests fits it well. But if the paradigm is instead the developing one I have sketched, in which the rights reserved in positive law to the United Nations are exercised in a de facto manner by regional organizations and individual states, then not only state interests narrowly conceived but also broadly recognized values must be taken into account.

At this point it may be possible to return to the matter of the skepticism regarding all uses of force in recent Catholic teaching, a skepticism that has tended toward a de facto denial of all contemporary resort to armed force under national authority, even when the just cause of self-defense is present. For the understanding of the current state of affairs I have sketched is one much more obviously akin to the situation employed by Ambrose to describe both the responsibility to use force in service of one's neighbor and the limits of such uses of force. The implication is that the denials of the right to resort to force even when just cause exists that were put forward in recent papal statements and paralleled in much other recent religious discourse on war do not apply when what is assumed is not a war of nations on the model of the two world wars, or a massively destructive nuclear exchange between the superpowers, but a limited application of force that is in accord with internationally accepted values and takes place with the express or tacit authority of the community of nations, even though national interests may also be served by such action.

Generals are often criticized for planning that aims to fight the previous war. Paul Fussell has put the matter more globally: "Everyone fighting a modern war tends to think of it in terms of the last one he knows anything about." Implicit in the argument I have made is that those who have aimed at defining the right of resort to armed force in the modern period have also thought of this right in terms of the last war they know anything about, from the national wars of the nineteenth century to the two world wars of the twentieth. Indeed, even the imagining of war among those who have focused on the destructive potential of nuclear weapons has proceeded from this understanding of war as an all-out, totalistic use of military might. From this reasoning to the effort to limit national resort to armed force to cases of defense, or even to condemn it outright, is not a large step. But in fact the form that contemporary uses of military force have taken is quite different from this, and the relation of national uses of such force to international sanction for the resort to force has developed accordingly.

It has been my thesis that in the contemporary world, the idea of just cause has developed in a way that allows individual states and groupings of states to employ limited force for reasons formerly denied to them, and to address issues that go beyond those formerly held to motivate states. In support of this thesis I have argued from a reading of the world as it exists after the end of the Cold War and from a reading of states and the state system as forces for justice in that world. Not by accident, the picture I have drawn closely matches the assumptions about states, the international order, and permissible uses of armed force found in the foundational just war theorists treated early in this essay. Nor is it accidental that the concept of just cause I have identified for the present state of affairs includes restoring that which has been taken wrongly (including violated rights and universal values), punishment of evil (uses of military means against troublers of international peace and security), and defense against military attacks not only when they are already under way but also while they are still in preparation.

From the perspective of persons who regard states as incurably venal and all uses of force in the modern era as disproportionately destructive, the position I have defined will seem an unwarranted and immoral loosening of strictures against the resort to force. From the perspective of political realism, on the other hand, my argument will seem to have gone too far, taking too much account of moral concerns, international standards, and values. But between these two perspectives lies precisely the territory of just war tradition, an understanding of statecraft in which the use of armed force in the service of justice is both permitted and restrained. That is the conception of just cause I have sought to define and whose implications I have sought to draw out.

About the author: James Turner Johnson is professor of religion at Rutgers University, where he also teaches in the graduate department of political science. Among the books he has written are Can Modern War Be Just? and The Quest for Peace: Three Moral Traditions in Western Cultural History.

Source: "Close Calls: Intervention, Terrorism, Missile Defense, and 'Just War' Today"