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Home , Justify (horse), Just war theory, Jus ad bellum, Reprisal, Surrender (military)

Just Cause for Jeff McMahan*

erhaps it should be rather hearten- widely accepted as just, such as the pun- ing that democratic leaders who ishment of wrongdoing and the spread of Pwish to take their countries to war the Christian religion. are now obliged to advertise the war as In this essay I advance a conception of having a “just cause.” Politicians now the requirement of just cause that is revi- routinely invoke this rather quaint sionist in the context of contemporary phrase drawn from the traditional theory , but that has roots in an of the just war. Indeed, when the admin- older of thought about the just istration of George H. W.Bush decided to war with which contemporary theorists invade Panama, it christened its war have lost touch to a considerable extent. “Operation Just Cause,” thereby appro- This revisionist conception has various priating a label that George W. Bush heterodox—indeed, heretical—implica- might later have found serviceable had it tions that I will highlight and defend: for still been available. But despite the example, that a just cause is necessary for increasing prominence of the notion of the satisfaction of any of the other condi- just cause in political discourse, there are tions of a just war, that there can be var- few serious discussions of it, and those ious just causes for war other than there are tend to be perfunctory. The defense against aggression, that both usual practice is to offer a simple charac- sides in a war can have a just cause, and terization of the requirement of just so on. The conception of just cause for cause—for example, that it is the require- which I will argue must ultimately be ment that there be a or compelling assessed by reference to the moral plausi- reason to go to war—and then to observe bility both of these implications and of that, at least until quite recently, contem- the larger understanding of a just war in porary just war theory and international which the conception is embedded. As I law have recognized only one just cause will make clear below, I mean by a just for war: self- or other-defense against war something more than merely a aggression. It is then often noted that the morally justified war. consensus on this point is currently being challenged by those who claim that the prevention of large-scale violations of people’s human rights by their own gov- ernment also provides just cause for war. *I am deeply grateful to Christian Barry, Allen Occasionally, skeptics of just war theory , David Lefkowitz, Larry May, Ron will also, for satirical effect, cite instances McClamrock, David Mellow, and for penetrating comments on an earlier draft of this from the classical literature of causes for essay, and to Thomas Hurka for illuminating discus- war that are now rejected but were once sion.

1 RESORT TO WAR, CONTINUATION goal, such as collective self-defense, there is OF WAR, AND TERMINATION OF no reason to suppose that a war may have WAR only one just cause. Even if the requirement of just cause applied only to the resort to In the just war tradition, just cause is one of war, there could in principle be two or more the requirements of —that is, just causes. It is even possible that, if there one of the conditions of justification for the were two or more just causes, no one on its resort to war. Contemporary just war theo- own would be sufficiently important to rists often assume, therefore, that the make the resort to war proportionate, requirement of just cause applies only to the though all together would be. And assuming initial resort to war, and that after war has that the requirement of just cause applies begun all that matters is how the war is con- not only to the initial resort to war but also ducted. But this cannot be right. It is possi- to the continuation of war, it is also possible ble that a war can begin without a just cause for there to be different just causes for the but become just when a just cause arises same war at different times. Consider, for during the course of the fighting and takes example, a war that has self-defense against over as the goal of the war. When this hap- unjust aggression as its initial just cause. It pens, it would be absurd to say that an unjust might be justifiable to continue the war even war has concluded and a new, just war has after the initial aggression had been defeated begun. Rather, one and the same war may in order to protect people in a justly occu- cease to be unjust and become just—just as pied area or to ensure the effective disarma- a war that begins with a just cause may con- ment of the aggressor. These would be just tinue after that cause has been achieved or causes that, while not part of the justifica- has simply disappeared on its own.1 But if a tion for the recourse to war, may legitimately war in progress can either acquire or cease to be pursued by the continuation of the war. have a just cause, then the requirement of The idea that war may not be continued just cause must apply not only to the resort in the absence of a just cause explains why it to war but also to the continuation of war.2 cannot be permissible to demand that an A just cause is, indeed, always required for adversary surrender unconditionally. For engaging in war. Just cause specifies the ends the idea that it could be permissible to for which it is permissible to engage in war, demand presup- or that it is permissible to pursue by means poses that the denial of any condition that of war. the other side might set for surrender would One important implication of the idea that any engagement in war requires a just 1 Grotius observed that “a war may be just in its origin, cause is that when the just cause of a war has and yet the intentions of its authors may become unjust been achieved, continuation of the war lacks in the course of its prosecution.”See , The justification and is therefore impermissible. Rights of War and (1625), trans. A. C. Campbell Just cause thus determines the conditions (London: M. Walter Dunne, 1901), p. 273. But a shift of intention does not entail the disappearance of the just for the termination of war. cause. Thus, Grotius goes on to say that “such motives, There are, however, complexities here of though blamable, when even connected with a just war, which it is important to be aware. Although do not render the war ITSELF unjust.” 2 Here I am in agreement with David Mellow, A Critique theorists in the just war tradition often write of Just War Theory (Ph.D. dissertation, University of as if just cause were always a single, unitary Calgary, 2003), p. 201.

2 Jeff McMahan itself be a just cause for the continuation of simply that war must have a just or worthy war. And that cannot be the case. Suppose goal. Nor is it a requirement that there be a the enemy insists on something perfectly worthy goal, the achievement of which reasonable as a condition of surrender—for would outweigh the bad effects of war. In the example, that the victors pledge not to kill just war tradition, the task of assessing the the prisoners of war they are holding. If it comparative importance of the goal or goals were permissible for the victors to insist on of war is assigned to the independent jus ad unconditional surrender and to continue bellum requirement of . Pro- the war until they secured it, that would pre- portionality requires, roughly, that the rele- suppose that it is permissible for them to vant bad effects attributable to the war must assert by means of war their alleged right to not be excessive in relation to the relevant withhold a pledge not to kill prisoners. good effects.3 According to the view I accept, This of course leaves open the question of it might in principle be possible for consid- what may be done when an adversary who erations of proportionality to be fully sub- has fought without justification demands as sumed within the requirement of just cause. a condition of surrender something to Many just war theorists would resist this which they are not entitled, yet the demand suggestion, however, because they believe is also of a type that it would not be permis- that the that count in the proportion- sible to resist by means of war. Suppose, for ality calculation are not restricted to those example, that an adversary who has been specified by the just cause. But unless just largely defeated militarily demands as a con- cause fully accounts for considerations of dition of surrender that they be allowed to proportionality, it ought not to say anything continue certain unjust domestic practices, about the scale, magnitude, or comparative such as certain forms of religious discrimi- importance of the goods to be achieved by nation (for example, providing state fund- war. For it would be uneconomical and ing for schools that promulgate the state indeed pointless to divide the work of religion, but not for others). Just as it may be weighing and measuring values between necessary for an individual not to resist cer- two requirements—for example, by having tain forms of wrongdoing when the only just cause stipulate that the goal of a war effective response would be inappropriate or must be to achieve some very great good, excessive in relation to the offense, so it may while proportionality would require that the be necessary in war to grant certain unde- served concessions when the only alterna- tive is to continue to fight without sufficient 3 justification. This is not, as some have supposed, a requirement that the bad effects, or expected bad effects, not exceed the good. A war might kill more people than it saves and THE MORAL PRIORITY OF JUST still be proportionate if, for example, the majority of CAUSE IN JUS AD BELLUM those killed are who fight without a just cause, so that the war achieves a net saving of the lives of those who are fully innocent in the relevant sense. I It is not only unjust aims that cannot per- will not pursue these complexities here. For discussion, missibly be pursued by means of war. There see Thomas Hurka, “Proportionality in the of are also many good or legitimate aims that War,” Philosophy & Public Affairs 33 (2005),pp.34–66; and Jeff McMahan and Robert McKim, “The Just War cannot permissibly be pursued by means of and the Gulf War,” Canadian Journal of Philosophy 23, war. The requirement of just cause is not no. 4 (1993), pp. 506–18. just cause for war 3 good be great enough to outweigh the rele- portionality requirement may have a larger vant bad effects of the war. role than many people suspect. Suppose, for I suggest, therefore, that just cause says example, that the defense of a state’s territo- nothing about considerations of scale or rial integrity against even partial annexation magnitude, but functions entirely as a by another state is a just cause for war, as restriction on the type of aim or end that many people believe. If just cause is not a may legitimately be pursued by means of matter of scale, then there would be a just war. It does not require that there be a great cause for war if a neighboring country were deal of good to be gained from war; nor does about to capture an acre of our territory on it imply that if there is a great deal of good to its border—an acre that it regards as a holy be gained, there is therefore a just cause. site, but that we are using only as a garbage This way of understanding the require- dump. In this case, the reason why it would ment of just cause parallels commonsense be wrong for us to go to war to retain our beliefs about the morality of individual possession of that acre is not that our aim action. Consider killing, for example, which would be too trivial to constitute a just cause; occurs on a large scale in war. Suppose—to it is, rather, that our just cause would be too alter the details of Dostoyevsky’s Crime and trivial for war to be proportionate. (Some- Punishment only slightly—that by killing thing of this sort might have been argued the miserly and misanthropic old money- with respect to Britain’s resort to war when lender, Raskolnikov could have divided her Argentina seized the Falkland Islands— wealth among a large number of poor peo- though defenders of that war argued that the ple, bringing significant benefits to each that proportionality calculation had to take into together would have greatly outweighed the account the importance of deterring even harm to her. Most people think that this is limited acts of aggression in order to uphold not even the right kind of justification for the principle of territorial integrity.) killing. It is widely held that only certain If this is right, there is a sense in which just types of aims—such as self-defense against cause does less work than many have sup- an unjust attack—can provide a justification posed, while proportionality does more. But for killing. In the same way, there are numer- there is also a sense in which just cause has a ous worthy and important goals that cannot kind of priority over all the other require- justify the resort to war, or the practice of ments of jus ad bellum. In most statements war. It cannot, for example, be a justification of the traditional theory, the following for going to war against a people that it requirements are included among the prin- would stimulate the world economy, no ciples of jus ad bellum: just cause, competent matter how great the economic benefits authority, right intention, reasonable hope would be.4 of success, necessity, and proportionality. I will soon turn to the question of how The satisfaction of each is held to be neces- those types of goal that might provide a just cause for war may be distinguished from those that cannot. For the moment I will say 4 See McMahan and McKim, “The Just War and the more about the relation between just cause Gulf War,” pp. 502, 512–13. There we acknowledge our and proportionality. debt on this point to Thomas Hurka, whose “Propor- tionality in the Morality of War” is one of the most Because just cause is only a restriction on probing and rigorous contributions to just war theory the type of aim that can justify war, the pro- in recent decades.

4 Jeff McMahan sary in order for the resort to war to be jus- cates the range of goods that may permissi- tified. And in that sense all the requirements bly be pursued by war, then no goods that are of equal importance. But I believe that fail to come within the scope of the just just cause has priority over the other valid cause, or are instrumental to achieving it, requirements in this sense: the others can- can count in the proportionality calculation. not be satisfied, even in principle, unless just If they did, that would imply that a war is cause is satisfied. justified, at least in part, by the fact that it Admittedly, this is not true of the tradi- would achieve certain goods that cannot tional requirement of competent authority, permissibly be achieved by means of war. but I reject that component of the tradi- (For those who are unconvinced by this sim- tional theory for reasons I will not present ple argument, I will say more on this point here.5 I also think that the plausible ele- in a later section on just cause and propor- ment in the requirement of “reasonable tionality.) hope of success” is subsumed by the pro- portionality requirement. JUST CAUSE AND JUS IN BELLO That leaves right intention, necessity, and proportionality. Although it is not obvious I have argued that none of the valid require- to me that right intention is a valid require- ments of jus ad bellum can be satisfied in the ment, suppose for the sake of argument that absence of a just cause. I also believe some- it is. It requires that war be pursued for the thing even more controversial, which is that reasons that actually justify the war. It insists the requirements of jus in bello also can- that those reasons not simply serve as a not—except in rare instances—be satisfied cover for the pursuit of other aims. What in the absence of a just cause. This is a highly this means is that right intention is the unorthodox claim. It is an axiom of con- requirement that war be pursued in order to temporary just war theory that whether achieve the just cause. Without a just cause, action in war is permissible or impermissi- therefore, there are no reasons that can ble does not depend on whether there is a properly motivate the resort to war. just cause. Just cause, on this view, governs There is, it might be argued, one way in only the resort to war. It is an ad bellum which right intention could be satisfied even requirement, and as such has no role in the in the absence of a just cause: if people falsely account of jus in bello. For the requirements believed that there was a just cause and of jus in bello and those of jus ad bellum are, fought with the intention of achieving it. Yet as puts it, “logically inde- it seems to me that this would clearly not be pendent”; hence, just as a war that one is jus- the right intention in the circumstances, tified in fighting may be fought in an unjust though it might well be a good intention. manner, so a war that is itself unjustified Consider next the requirement of neces- sity. This requirement demands that war be 5 a necessary means of achieving the just Although I reject competent authority as a necessary condition of a just war, I concede that it is of practical cause. The claim that war is necessary for importance to restrict the authority to take certain actions something other than the achievement of a to certain individuals or bodies when we seek to give insti- just cause has no justificatory force. tutional expression or embodiment to the requirements of a just war. It may be that, once certain institutions are In the case of proportionality, there is an established, some just causes for war can permissibly be equally simple argument. If just cause indi- pursued only by those with proper authority. just cause for war 5 may nevertheless be fought in a just manner Similarly, if soldiers lack a just cause, there or, as Walzer says, “in strict accordance with are no goods that they are justified in pursu- the rules.”6 The requirements of jus ad bel- ing by means of war. So even if there are lum are, moreover, thought to apply only to goods for which belligerent action is neces- the political leaders, those with the authority sary, they are not goods that can permissibly to commit a people to war, and not to those be achieved in that way. And when there are who do the actual fighting. On this view, no goods that may be pursued by means of there is a moral division of labor that makes war, there are no goods that can properly be soldiers responsible for adherence only to the weighed against the bad effects that an act of principles of jus in bello, which must there- war would cause; therefore, no act of war fore be satisfiable whether or not their war can be proportionate in the absence of a just meets the conditions of jus ad bellum.It cause.8 In short, when there is no just cause, would be intolerable to suppose that all sol- acts of war can be neither discriminate, nec- diers who are commanded to fight in an essary, nor proportionate. unjust war, or who fight in such a war with- There is, I concede, a small class of excep- out knowing that it lacks a just cause, are for tions to this general claim. These are acts of that reason criminals or even murderers. war by those who lack a just cause that are It may seem obvious, in any case, that at necessary to prevent their adversaries from least some of the requirements of jus in bello acting in ways that would be seriously can be satisfied even by those who fight wrong—for example, to prevent those fight- without just cause. The requirement of dis- ing with a just cause from pursuing it by ille- crimination, for example, requires only that gitimate means, such as by attacking people combatants restrict their attacks to military who are innocent in the relevant sense as a targets—that they target only other combat- means of coercing those people’s govern- ants and not noncombatants. This is ment to surrender.9 implicit in the widely used alternative label This concession necessitates that we dis- for the requirement: the “requirement of tinguish between a just cause for war, which noncombatant immunity.” can contribute to the justification for going But this is in fact just one interpretation to war and may legitimately be pursued by of the requirement of discrimination, which means of war, and what I will call a discrete in generic terms is simply the requirement just aim, which cannot contribute to the jus- to discriminate between legitimate and ille- tification for the resort to war or for its con- gitimate targets and to make deliberate tinuation, but may legitimately be pursued attacks only on the former. In my view, by means of war if war is in progress. Such which I have defended elsewhere, the dis- aims are “discrete”because they occur in iso- tinction between legitimate and illegitimate targets does not coincide with that between combatants and noncombatants. Rather, 6 what discrimination requires is that soldiers Michael Walzer, Just and Unjust (Har- mondsworth, U.K.: Penguin, 1977), p. 21. target only those who are morally responsi- 7 For elaboration, see Jeff McMahan, “The of ble for an unjust threat or for some other Killing in War,” Ethics 114, no. 4 (2004), esp. pp. 718–29. 8 grievance that provides a just cause for war. I have argued at length for the claim that those who fight without just cause cannot satisfy the jus in bello If that is right, soldiers who lack a just cause requirement of proportionality. See ibid., pp. 708–18. 7 also lack legitimate targets. 9 Ibid., pp. 712–14.

6 Jeff McMahan lation and are unconnected with the larger what types of aim can be just causes for war aims of the unjust war of which they are a that is also heretical, given the consensus that part. The permissibility of pursuing a dis- has developed between and crete just aim by means of war is doubly contemporary just war theory that defense conditional: it may be pursued if war is against aggression is the sole just cause for already in progress and if the wrong to be war (with the possible exception of the pre- prevented cannot be avoided by surrender- vention of large-scale violations of human ing on morally acceptable terms. rights, such as genocide). The view about In general, however, a just cause is neces- what may be a just cause for war that I will sary for an act of war to be justified. It is for defend does, however, have roots in the writ- this reason that war must cease once the just ings of earlier just war theorists and earlier cause has been achieved. Soldiers may not theorists of international law. continue to fight once the aims that justified , for example, was close their fighting have been achieved.And if this to the truth when he wrote that “a just cause is true, it should also be true that they may is required, viz. that those who are to be not fight at all if there are not and never were warred upon should deserve to be warred any aims that justify their being at war. Just upon because of some fault.”10 This claim is, cause is necessary not only for it to be per- however, in one respect too narrow and in missible for political leaders to resort to war; another too broad. It is too narrow in its it is also necessary for it to be permissible to insistence that it is necessary for just cause participate in war. that those attacked should deserve to be This is not to say that those who partici- attacked. I take the claim that a person pate in war without a just cause are neces- deserves to be harmed to imply that there is a sarily culpable or deserving of punishment. moral reason to harm him even when harm- Just as in the law a person may be fully excul- ing him is unnecessary for the achievement pated for action that is objectively in breach of any other aim—for example, when harm- of a statute, so most soldiers who fight with- ing him would not prevent, deter, or rectify out a just cause may have a variety of excuses any other harm or wrong. In this sense, peo- that partially or even fully exculpate them. ple seldom if ever deserve to be warred upon. And even if the excuses that soldiers have for The notion I would substitute for desert is fighting in an unjust war never fully excul- liability. To say that a person is liable to be pate them, it is possible, and almost certainly attacked is not to say that there is a reason to highly desirable, not to treat mere participa- attack him no matter what; it is only to say tion in an unjust war as punishable under that he would not be wronged by being international law. attacked, given certain conditions, though perhaps only in a particular way or by a par- THE CONNECTION BETWEEN JUST ticular agent. This notion is broader than CAUSE AND MORAL LIABILITY TO ATTACK 10 Thomas Aquinas, Summa Theologiae,IIaIIae,q.40, art. 1, resp., quoted in Jonathan Barnes, “The Just War,” These claims about the dependence of jus in in Norman Kretzmann, Anthony Kenny, and Jan Pin- bello on just cause deviate substantially from borg, eds., The Cambridge History of Later Medieval Philosophy (Cambridge: Cambridge University Press, the currently orthodox understanding of the 1982), p. 777. Since the only is to the text, just war. I will now advance a view about I assume that the translation is Barnes’s own. just cause for war 7 desert in that, while desert implies liability, recting the wrong that has already been liability does not imply desert. done. Although liability to attack usually or The connection I am claiming between perhaps always arises from action that is just cause and liability may be found, though wrongful, there is no necessary connection not altogether explicitly, in the work of some between liability and punishment or retri- of the earlier jurists writing in the just war bution. To say that a person is liable to be tradition. These writers typically insisted harmed even though he does not deserve to that just cause is founded in an injury, by be harmed is just to say that if it is unavoid- which they meant a wrong or a violation of able that someone must be harmed, there is rights. Hugo Grotius, for example, noted reason that he should be the one who is with approval that “St.Augustine, in defining harmed and that he will not be wronged by those to be just wars, which are made to being harmed. avenge injuries, has taken the word avenge in Substituting the notion of liability for a general sense of removing and preventing, that of desert, we can say that there is just as well as punishing aggressions.”12 Similarly, cause for war only when those attacked have Emmerich de Vattel claimed that “the foun- made themselves liable to be warred upon. dation, or cause of every just war is injury, But Aquinas’s claim that the basis of their either already done or threatened....And,in liability is fault, or culpability, may be both order to what is to be considered too broad and too strong. It is possible to as an injury, we must be acquainted with a read his claim as implying that any fault that nation’s rights....Whatever strikes at these might make a person deserving of harm rights is an injury, and a just cause of war.”13 could be a basis of liability to attack, in But the most explicit of the classical writers which case it would be too broad. For the is , who argued that relevant fault must be specifically for a a political leader “cannot have greater wrong that war against the perpetrators authority over foreigners than he has over his would prevent or redress. And the insis- own subjects; but he may not draw the sword tence on fault, or culpability, may in princi- against his own subjects unless they have ple be too strong in that it is possible— done some wrong; therefore he cannot do though not likely—that a people could so against foreigners except in the same make themselves liable to be warred upon by being morally responsible, though fault- lessly, for a wrong that war against them 11 Some people accept that if you reasonably but mis- 11 would prevent or redress. takenly believe that I am culpably trying to kill you, you Here, then, is a statement of the formal may be morally and legally justified in killing me. Even if this were so (I think it is not, but I cannot argue for concept of just cause. There is just cause for that here), this would not imply that I would be liable war when one group of people—often a to be killed. I cannot be made liable by your mistake, state, but possibly a nation or other organ- even if it is a reasonable one. The basis of moral liabil- ized collective—is morally responsible for ity must be some form of responsible action by the per- son who is liable. For discussion, see Jeff McMahan, action that threatens to wrong or has “The Basis of Moral Liability to Defensive Killing,” already wronged other people in certain Philosophical Issues 15 (2005, forthcoming). 12 ways, and that makes the perpetrators liable Grotius, The Rights of War and Peace,p.76. 13 Emmerich de Vattel, The Law of Nations (1758), trans. to military attack as a means of preventing Joseph Chitty (Philadelphia: Johnson & Co., 1863), p. the threatened wrong or redressing or cor- 302.

8 Jeff McMahan circumstances....It follows from this that cance: combatants pose a threat to others; we may not use the sword [that is, resort to noncombatants do not. Thus, because all war] against those who have not harmed us; to kill the innocent is prohibited by natural 14 law.”14 It is an implication of this view that Francisco de Vitoria,“On the ,”in Political Writ- ings, Anthony Pagden and Jeremy Lawrance, eds. (Cam- those who fight by permissible means in a bridge: Cambridge University Press, 1991), pp. 303–304. just cause are innocent and may not permis- 15 Ibid., p. 307. Vitoria seems to accept a subjective sibly be attacked. account of justification, according to which it is wrong To kill the innocent,Vitoria says, is imper- for a person to fight in a war that he believes to be unjust, even if his belief is mistaken (p. 308). This missible. And the innocent are those who account of justification may not be fully subjective, have done no wrong; they are those who however, because elsewhere Vitoria suggests that only have done nothing to make themselves reasonable belief is sufficient for justification (p. 306). But this means that he accepts that a person can be jus- morally liable to be killed. This, as Vitoria tified in fighting in an unjust war, provided that he rea- recognizes, supports the view for which I sonably believes that it is just; and Vitoria suggests that argued above—that the requirement of dis- whenever there is uncertainty about whether a war is just, it is reasonable for a citizen to accept the assurance crimination cannot be satisfied in the of his government that it is just (pp. 312–13). absence of a just cause. For a war that lacks 16 Francisco Suárez, “On War” (Disputation XIII, De a just cause is a war fought against those who Triplici Virtute Theologica: Charitate) (c. 1610), in Selec- have not made themselves liable to attack. It tions from Three Works, trans. Gladys L. Williams, Ammi Brown, and John Waldron (Oxford: Clarendon is a war fought against the innocent. Vitoria Press, 1944), pp. 845–46. therefore concludes that if a person is cer- 17 See, e.g., , “War and Massacre,” in tain that a war is unjust, he must not fight in Charles R. Beitz, Marshall Cohen, Thomas Scanlon, and A. John Simmons, eds., International Ethics (Princeton: it, even if he is commanded to do so by a Princeton University Press, 1985), p. 69; Anthony Kenny, legitimate authority. For “one may not law- The Logic of Deterrence (London: Firethorn Press, 1985), fully kill an innocent man on any authority, p. 10; and Michael Walzer, Just and Unjust Wars,p.145. Elizabeth Anscombe, another influential contributor to and in the case we are speaking of the enemy the literature on the just war, is inconsistent on this must be innocent. Therefore it is unlawful to point. In her justly celebrated pamphlet opposing kill them.”15 This view—that only those who Oxford’s award of an honorary degree to President Tru- fight in an unjust war are liable to attack—is man (on the ground, in effect, that mass murderers ought not to be awarded honorary degrees), she wrote shared by Francisco Suárez, who asserts that that “‘innocent’ . . . is not a term referring to personal “no one may be deprived of his life save for responsibility at all. It means rather ‘not harming.’ But reason of his own guilt”; thus, the innocent the people fighting are ‘harming,’ so they can be attacked.” (Anscombe, “Mr. Truman’s Degree,” in include all those who “have not shared in the Ethics, Religion, and Politics: Collected Philosophical 16 crime nor in the unjust war.” Papers, vol. 3 [Minneapolis: University of Minnesota Contemporary just war theorists think Press, 1981], p. 67.) But in a later paper she wrote that “what is required, for the people attacked to be non- that this is a crude mistake.“Innocent,”they innocent in the relevant sense, is that they should them- point out, contrasts in this case with “threat- selves be engaged in an objectively unjust proceeding ening,” not with “guilty” or “culpable.”Any- which the attacker has the right to make his concern; one who poses a threat is noninnocent, and or—the commonest case—should be unjustly attack- ing him.” (“War and Murder,” in the same volume, p. therefore soldiers on both sides are nonin- 53.) In this quotation, “non-innocent” means neither nocent in the sense that is relevant for deter- “harming or threatening” nor “guilty,” but “engaged in mining liability to attack.17 This, after all, is objectively wrongful action.” So when she wrote the second essay, she had reverted to a position more in what gives the between combat- keeping with the older just war tradition but inconsis- ants and noncombatants its moral signifi- tent with the contemporary orthodoxy.

just cause for war 9 soldiers are noninnocent, even those who tion is innocent, but treats those who fight have a just cause are not wronged when they without a just cause as wrongdoers. To are killed by those who lack a just cause. Sim- regard the liability of soldiers as a function ply to be a soldier is to make oneself liable to merely of their role as combatants not only be killed. limits their liability to matters of jus in bello, But this is an implausible understanding and thus rules out the legitimacy of punish- of the basis of liability. If simply posing a ment merely for fighting on the wrong side, threat were a basis of liability to attack, those but also has as a corollary the prohibition of individuals who engage in justified self- deliberate attacks on . The separa- defense would thereby make themselves tion of jus in bello from the question of just liable to preemptive counterattack by those cause thus effectively limits or constrains the who have wrongfully attacked them. And savagery of war. police would not be wronged by being pre- What this view leaves out, however, is the emptively attacked by those whom they insight of the classical jurists—that people were about to attack in order to prevent are treated unjustly if they are deliberately them from committing crimes. killed without having done wrong. The cur- Why, then, do most contemporary just rently orthodox view, which holds that the war theorists think that such an account of moral status of soldiers is unaffected by liability is appropriate in the case of war? I whether they have a just cause, implies that a suspect that it has to do with their convic- person who takes up arms to defend himself tion that most ordinary soldiers are not and others from a threat of unjust aggression criminals, even if they fight in a war that thereby makes himself morally liable to be lacks a just cause. They believe that it is rea- killed by the aggressors, who then act per- sonable to absolve ordinary soldiers of missibly, and do him no wrong, if they go on responsibility for determining whether a to kill him. It is very hard to believe that this war is just or unjust. That responsibility lies could be right. Moreover, at least some of the with others. Soldiers may thus see them- practical benefits that are attributed to this selves and their adversaries as engaged in an orthodox view may be attained just as well by activity dictated by goals for which they are regarding some of those who fight without a not responsible and over which they have no just cause as excused for rather than as control. They are bound by a code of honor morally justified in fighting. that is suited to and distinctive of their role The contemporary theory of the just war as warriors, but they are not holy warriors seems, in short, to be less concerned than the with a mandate to eradicate . They must tradition it claims to represent with what is not, for example, take vengeance on prison- just and unjust in war, and is instead more ers or seek to punish the vanquished. This is concerned with the consequences of war the only fair way for soldiers to view and and the conventions that are useful in con- treat other soldiers, given the various pres- trolling those consequences.18 sures and constraints under which they all must act. And, it is often argued, this way of understanding the morality of war also 18 For an argument that it is necessary for the law of war works out far better in practice than a view to diverge from the underlying, nonconventional morality of war, see Jeff McMahan, “The Laws of War that treats those who fight with a just cause and the Morality of War,” in David Rodin and Henry as innocent in the way their popula- Shue, eds., Just and Unjust Warriors (forthcoming).

10 Jeff McMahan A SUBSTANTIVE ACCOUNT OF THE Contrary to what I wrote earlier, this gives REQUIREMENT OF JUST CAUSE considerations of scale a role in the concept of just cause.20 Only aims that are suffi- Thus far I have offered only a formal ciently serious and significant to justify account of the requirement of just cause, killing can be just causes. Beyond this, how- claiming that there is a just cause for war ever, considerations of scale are irrelevant to only when those attacked are liable to be just cause. warred upon. A substantive account of just Let us assume that people can make cause has to go further by providing a crite- themselves liable to be killed (for example, rion for determining what sorts of action in self-defense or as punishment) only by engender liability to military attack. of seriously wronging or threatening The classical jurists to whom I have to wrong others. On this assumption, the referred typically offer a short list of just just causes for war are limited to the preven- causes for war. The jurists tend to agree that tion or correction of wrongs that are serious the just causes for war are basically these: enough to make the perpetrators liable to be defense against unjust threats; recovery of or killed or maimed. indemnity for what has been wrongfully If this is right, it does not automatically taken, or compensation for the violation of generate a list of just causes, but it does pro- rights; and punishment of wrongdoing, not vide some much-needed guidance in identi- solely for the purpose of retribution but to fying what may be a just cause for war. We prevent or deter further wrongful action by can, in particular, consult our beliefs— the culprit or by others.19 These suggested which are quite robust and stable—about just causes for war are all consistent with the which kinds of wrong are sufficiently serious insistence that, for war to be just, those that the killing or maiming of the perpetra- attacked must be morally liable to attack. tor could be justified if it were necessary to But a unified account of the morality of war prevent or correct the wrong. Most people ought also to explain why certain forms of agree, for example, that one person may per- action give rise to liability to attack while missibly kill another if that is necessary to others do not. In this section I will offer a prevent the other person from wrongfully preliminary sketch of a method for deter- killing, torturing, mutilating, raping, kid- mining whether a certain goal can be a just napping, enslaving or, perhaps, imprisoning cause for war. her. Many people would also accept that it War involves killing and maiming; or, can be permissible to kill in defense against rather, war that involves killing and maim- unjust and permanent expulsion from one’s ing is what requires a just cause. In principle home or homeland, and even, perhaps, in and even in law, there might be a wholly defense against theft—though here ques- nonviolent war—for example, one declared tions of scale are obviously relevant to pro- by opposing belligerent powers but termi- nated by agreement before their forces 19 See, e.g., Grotius, The Rights of War and Peace,pp. engage. That is not my topic. War, as I 75–76; Vitoria,“On the Law of War,”pp. 302–306; Vattel, understand it here, necessarily involves The Law of Nations,pp.301–14; and Samuel Pufendorf, killing and maiming, typically on a large De Jure Naturae et Gentium, Libri Octo (Oxford: Clarendon Press, 1934), p. 1294. scale. A just cause, then, has to be a goal of a 20 I am grateful to Rachel Cohon for calling this to my type that can justify killing and maiming. attention.

just cause for war 11 portionality. It is only when theft would sive war to be just. This is clearest in cases in threaten extreme and protracted deprivation which defense against wrongful aggression that killing could be a proportionate means fails and the aggressor achieves its aim—for of defense. Perhaps what we should say is not example, by seizing and occupying territory, that it can be permissible to kill to prevent or by imposing an alien or collaborationist theft, but that it can be permissible to kill to government that will do its bidding. In such prevent any sort of act that would wrongfully cases it would be absurd to suppose that the reduce a person to utter destitution. victims lose their rights when they lose their If each of these types of wrong is such war of defense. If it later becomes possible that its prevention—or, when possible, its for them (or third parties acting on their correction—can justify killing, then its pre- behalf) to reassert through armed rebellion vention or correction can also be a just the rights that were violated by the earlier cause for war. There are, of course, com- aggression, and thereby to recover the terri- plexities and complications involved in tory or political independence of which they extrapolating from the individual to the were unjustly deprived, they will not wrong collective level. Except for heuristic pur- the aggressor if they do so. Successful poses, we cannot rely on what Walzer calls aggressors remain liable to attack as long as the “domestic analogy,”applying the princi- they retain the spoils of their wrongful ples that govern relations between individ- aggression. (Recall that just cause is not the uals to relations between collectives, as if sole condition of a just war. War must also collectives were individuals. For a collective be, among other things, necessary. Unjust is not an individual: it does not have a - occupation or political subordination may gle will, a single set of desires, or a unitary often be more effectively defeated, and with good. Extrapolation has to proceed by com- far fewer casualties, by means of nonviolent position rather than by analogy, but even resistance, particularly when the occupier is the most reductive form of individualism a democratic society with a free press—as, must take account of distinctively collective for example, Israel is.21) goods, such as collective self-identification There is, however, a moral statute of lim- or collective self-determination, and thus itations here, particularly with respect to recognize that there may be wrongs that are territorial rights. If, following an unjust not entirely reducible to wrongs against seizure of territory, enough time passes for a individuals because they have a collective as new society with its own infrastructure to their subject. I cannot pursue these compli- arise within the territory, the members of cations here. that society may acquire an increasingly Instead, I will explore in the following strong moral claim to stay, particularly as section a few of the implications of the view I have sketched. 21 I believe, though this cannot be proven, that if the JUST AND UNJUST CAUSES Palestinians had produced a leader like Gandhi rather than Arafat, they could have had their own state decades ago and could now be free and prosperous, and that Recovery of Goods Lost to Prior Aggression this, by removing one potent source of grievance and In morality, if not in law, just cause is not humiliation among Arabs and Muslims, could in turn have helped forestall some of the worst instances of limited to self-defense against armed aggres- recent . Palestinian terrorism has, in short, sion. It is, for example, possible for an offen- been not only morally shameful but also self-defeating.

12 Jeff McMahan new generations who are entirely innocent for example, either be requested, or there of the initial aggression establish their own must at least be compelling evidence that lives there. This is why Israeli settlements the intended beneficiaries would welcome outside the borders Israel was assigned by rather than oppose intervention by the par- the UN are properly regarded as instru- ticular intervening agent or agents. (One ments of insidious territorial aggression. reason why the American invasion of Iraq in The longer the settlers stay, the more they 2003 was not a justifiable instance of build, and the more children they have, the humanitarian intervention is that there was stronger their moral claim to the land no evidence that ordinary Iraqis wanted to becomes. Consequently, Israelis who move be freed from the Ba’athist dictatorship by to the settlements voluntarily are morally the United States—a country that a little responsible participants in unjust aggres- more than a decade earlier, and under the sion, and as such are morally liable to defen- leadership of the current president’s father, sive attack—though their young children had bombed their capital, decimated their are not. Even when they do not themselves civilian infrastructure, and successfully bear arms, which they usually do, their pres- pressed for the institution and perpetuation ence in the occupied territories is possible of sanctions that subsequently resulted in only because of a background threat of mil- many thousands of deaths among civilians.) itary protection. There is, therefore, a case Many people have thought that consider- for regarding them as having sta- ations of national self-determination mili- tus and thus as being liable, even according tate against humanitarian intervention. to the orthodox theory of the just war. If This objection is often specious, however, there are those who refuse to bear arms, they when the intervention is desired by the vic- are morally like civilians who make them- tims of governmental persecution. For in selves liable by voluntarily acting as shields such cases the gulf between victims and per- for combatants engaged in territorial petrators is typically so wide that there is no aggression, and who thereby facilitate longer (if there ever was) a single collective aggression by forcing the other side to have “self” whose is threatened, but to kill civilians in order to resist. rather two or more distinct collective selves, one of which is engaged in wrongful action Humanitarian Intervention that is not protected by its right of self- Governments sometimes gravely wrong determination.22 There are various other their own citizens, particularly members of objections to humanitarian intervention, ethnic or other minorities or political dissi- but the most serious are of a pragmatic dents. These wrongs may make their perpe- nature, having to do with such considera- trators liable to attack for purposes of tions as the likelihood of self-interested defense or correction. Just as resistance to abuse of any recognizing the legiti- these wrongs may in rare instances lead to macy of war for altruistic reasons. But no justified by the victims against the such objections show that certain aims of perpetrators, so military intervention by third parties may also be justified on behalf of the victims. There are, of course, various 22 For detailed discussion, see Jeff McMahan, “Inter- conditions that must be met if humanitar- vention and Collective Self-Determination,” Ethics  ian intervention is to be permissible. It must, International Affairs 10 (1996), pp. 1–24. just cause for war 13 humanitarian intervention cannot be just I have argued, that it can be a just cause for causes for war. war. For a just cause is any aim that may legit- imately be pursued by means of war; it may The Prevention of Future Aggression justify only a phase of a war or even just a sin- It is highly contentious whether the preven- gle act of war without justifying the resort to tion of future aggression can be a just cause war or the war as a whole. for war. By prevention of future aggression I I once thought, as these classical writers mean action taken to address a threat of imply, the prevention of future aggression unjust attack that is neither in progress nor could not on its own be a just cause for war. imminent, but temporally more remote. In a paper drafted during the Gulf War of Whether this can be a just cause for war is 1990–91, Robert McKim and I drew a dis- obviously central to the issue of the legiti- tinction between an independent just cause, macy of . which could justify war or the resort to war Many theorists of the just war accept that on its own, and a conditional just cause, the prevention of future aggression can be a which could contribute to the justification legitimate aim of war once war is already in for war, but only when triggered or activated progress. Samuel Pufendorf, for example, by the presence of an independent just writes: “It is permitted to apply force against cause.25 I thought at the time that the pre- an enemy not only to the point where I have vention of future aggression could be only a repelled the danger which he threatens conditional just cause—that is, that it could against me, or where I have recovered or legitimately be pursued only when war was wrested from him that which he has unjustly already justified by reference to an inde- seized from or refused to furnish me; but I pendent just cause arising from a wrong that can also proceed against him in order to had been done, was being done, or was on obtain a guarantee for the future. So long as the verge of being done. I thought that only the other allows this to be wrested from him an act that made a country liable to attack through force, he gives sufficient indication for some reason other than prevention that he still intends to injure me even there- could also make it liable to preventive attack. after.”23 Similarly, Vattel acknowledges that I now think that this view is mistaken. prevention through forcible disarmament It is true that when the prevention of can be permissible once aggression has future aggression is a just cause for war, it is occurred. But he insists on a prior injury as a in most cases because a country is already condition of legitimacy: “For an injury gives committing a wrong—for example, is us a right to provide for our future safety, by engaged in an act of unjust aggression—that depriving the unjust aggressor of the means makes it simultaneously liable to both of injuring us.”24 Here Vattel echoes his pred- ecessor, Vitoria, who, as I noted above in the discussion of moral liability to attack, 23 Craig L. Carr, ed., The Political Writings of Samuel asserted that violence may be done only to Pufendorf, trans. Michael Seidler (New York: , 1994), p. 259. those who have “done some wrong.” If, as 24 Vattel, The Law of Nations,p.310. these writers claim, the prevention of future 25 McMahan and McKim, “The Just War and the Gulf aggression can be a legitimate aim of war War,” pp. 502–506. In this article we used the terms “suf- ficient just aim”and “contributing just aim,”rather than once war is already in progress, that implies, the more perspicuous terms “independent just cause” on the understanding of just cause for which and “conditional just cause.”

14 Jeff McMahan defensive and preventive attack. In these that, all things considered, it is nonetheless cases, a single wrongful act makes the justifiable for A to avoid an otherwise offending country liable to attack for more inevitable defeat at the hands of B by going than one reason. But all that is necessary for to war against C in order to be able to deploy prevention of future aggression to be a just troops there, provided that it will withdraw cause is that a country should have done immediately after fighting off the invading something to make itself liable to be forces from A. (One historical case that attacked as a means of preventing it from approximates this scenario is Russia’s war committing a wrong in the future. And the against Finland in 1939–40. The Russian kind of action that engenders this form of government believed that control of Finnish liability need not engender liability to attack territory within range of Leningrad for any other reason. In other words, the was necessary to protect the from Nazi prevention of future aggression may, in . It offered the Finns an some cases, be the sole just cause for war. In exchange of territory, but the offer was these cases, the country that is liable to pre- refused, and the Russians then went to war ventive attack may be guilty of no wrong to capture the territory they thought was other than the kind recognized in the area of necessary as a buffer against the Nazis. One criminal law concerned with conspiracy: the reason this is only an approximation of my kind of wrong that involves collaborators hypothetical example is that the Finns had manifestly intending and actively preparing good reason not to trust Stalin’s assurances to commit a crime. In order for this kind of that Russia’s aims were limited, since, among activity to constitute a just cause for war, the other things, Russia had only a short time intended wrong must be grave enough that earlier collaborated with the Germans in its prevention could justify killing and carving up Poland.) maiming.26 Given that C is not morally required to sacrifice its territory for the sake of A, it Just War as One Type of Morally seems that C does nothing to make itself Justified War liable to attack by A. On the account I have Consider now a different kind of case. Sup- offered, therefore, A does not have a just pose that country A is about to be unjustly cause for war against C. Yet if A is neverthe- invaded by a and more powerful less morally justified in going to war against country, B. A’s only hope of successful C, it must be possible for there to be wars defense is to station forces in the territory of that are morally justified yet unjust. A war is a smaller, weaker, neighboring country, C, in just when there is a just cause and all other order to be able to attack B’s forces from pre- relevant conditions of justification are also pared positions as they approach A along the border between B and C. A’s government requests permission from the government 26 For a more detailed discussion of these issues, see Jeff of C to deploy its forces on C’s territory for McMahan,“Preventive War and the Killing of the Inno- cent,” in David Rodin and Richard Sorabji, eds., The this purpose, but C’s government, foreseeing Ethics of War: Shared Problems in Different that allowing A to use its territory in this way (Aldershot, U.K.: Ashgate, 2005), pp. 169–90. See also would result in considerable destruction, Allen Buchanan and Robert O. Keohane, “Governing the Preventive Use of Force: A Cosmopolitan Institu- denies the request. Suppose that C is within tional Proposal,” Ethics  International Affairs 18,no.1 its rights to deny A the use of its territory but (2004),pp.1–22. just cause for war 15 satisfied. But, while all just wars are morally stopping the violations, they do not obvi- justified, it seems that not all morally justi- ously make that government liable to fur- fied wars are just wars. As the example of A, ther or harsher attacks intended to warn B, and C suggests, there seem to be wars that other governments of the penalties for vio- are morally justified despite their requiring lating human rights. And certainly the vio- the targeting of those who are innocent in lation of its citizens’ human rights cannot the relevant sense, so that at least some nec- make a government liable to attack as a show essary phases of the war, and perhaps indeed of force intended to deter other countries all of its phases, lack a just cause. The form from engaging in the different crime of of justification in these latter cases is famil- aggression. iar: in rare circumstances, considerations of Yet deterrence of others can be a just cause consequences override constraints on action and thus contribute to the justification for that would otherwise be decisive. It is com- war if the wrong committed by the country monly recognized, for example, that it can in that is attacked would itself otherwise principle be permissible intentionally to increase the probability that other countries harm or kill an innocent person if that is would commit wrongs of a sort that would necessary to avert some great disaster. The constitute a just cause for war. For in that case necessity of preventing the disaster out- the country’s wrongful action would make it weighs the grave injustice done to the indi- to some degree responsible for the increased vidual victim. risk of further wrongful action by others. If war may be justified in the absence of a That responsibility makes it liable to belliger- just cause, one may wonder how significant ent action necessary to deter the wrongs that the notion of just cause can be.27 The answer its own action had made more likely. Sup- is that the presence or absence of a just cause pose, to take a historical example, that has a dramatic effect on the stringency of the Argentina’s seizure of the Falkland Islands, if proportionality requirement. When there is unopposed, would have emboldened other no just cause, all those who are targeted in countries wrongfully to seize by force certain war are innocent. And harms inflicted on territories to which they believed they had a the innocent weigh more heavily against the historical claim. In that case, the aim of goals of a war than harms inflicted on those restoring the deterrence of such ambitions to who are liable. The burden of justification is previous levels could have contributed to the therefore very substantially greater in the justification for Britain’s going to war and for absence of a just cause. its action during the war. Although deterrence may thus be a just Deterrence cause, it is, unlike the prevention of future Deterrence is problematic as a just cause for aggression, unlikely ever to be the sole just the same reason it is problematic as the sole cause for war. For any action that is suffi- aim of punishment. In both cases it seems cient to make a country liable to be used as objectionable because it uses the harming of a means of deterring others will almost nec- some as a means of influencing the action of essarily be the sort of action that gives rise to others. So, for example, even if a govern- another just cause as well. For example, it ment’s systematic violations of the human rights of some of its citizens are sufficient to make it liable to attack for the purpose of 27 Thanks to Jon Mandle for pressing me on this point.

16 Jeff McMahan seems that a country can make itself liable to self-government from suppression by a attack as a means of deterring others from tyrannical regime, this suggests the need for engaging in aggression only by itself engag- a further category of intervention—namely, ing in aggression, in which case defense intervention that is necessary for the defense against that aggression will also be a just of the rights of a people against violation by cause. And the same seems true for other others within their own state, particularly by wrongs that may make a country liable to be their own government. But note that what attacked for the purpose of deterrence. is really at issue here is not the concept of humanitarian intervention or the right to Democratization democracy, but the permissibility of mili- The Bush administration has contended tary intervention to defend a people’s right that war can be justified as a means of bring- to collective self-determination. Such inter- ing democracy to people who lack it—that vention might be justified even if what peo- is, that democratization can be a just cause. ple want is not democracy but rule by what But one does not even need a substantive they perceive to be the law of god, while their account of just cause to rule this out; it is government insists on subjecting them to ruled out by the formal claim that just cause some different form of rule instead. One is always correlated with liability to attack important question here is whether inter- on the part of those targeted for attack. For ventionary war could be justified even when people cannot be liable to killing and maim- a people’s aspirations for self-determination ing simply for failing to organize their inter- were being suppressed not by force but nal affairs in a democratic manner, even if merely by a threat of force. If what I have democracy would be better for them and for claimed earlier is right, the way to think their relations with others. about this is to ask whether those who are There might be a just cause for war if a responsible for the suppression thereby people were being forcibly prevented by a make themselves liable to be killed if that is tyrannical government from organizing necessary in order to end it. A useful test is themselves democratically, for then the gov- to consider whether the people whose rights ernment itself might be liable to attack for are being violated would be justified in wronging its citizens. A war to stop the sup- resorting to armed rebellion in defense of pression of a people’s democratic aspira- those rights. If they would be, that suggests tions would not be a war for the promotion that external military intervention on their of democracy, but would instead come behalf would be justified as well, other within the category of humanitarian inter- things being equal. vention, as its fundamental aim would be to stop a government from violating the rights JUST CAUSE AND of its citizens. PROPORTIONALITY This admittedly presupposes a concep- tion of humanitarian intervention that is I claimed in the earlier section on the moral rather more expansive than the prevailing priority of just cause that only the achieve- conception. If the concept of humanitarian ment of aims that are specified by a just intervention is insufficiently elastic to cause can contribute to the satisfaction of include interventions that are necessary to the ad bellum proportionality requirement. defend the right of a people to democratic No other goods that might be realized by just cause for war 17 war may weigh against the bad effects that It seems, therefore, that the only goods would be attributable to the war in deter- that can count in the ad bellum propor- mining whether war would be proportion- tionality calculation involve the prevention ate. In light of the formal and substantive or correction of wrongs for which those elements of the account of just cause I have warred against are responsible (for again it sketched, it may now be clearer why this is would be obviously unjust to prevent or so. A just cause is necessarily connected with correct a wrong by going to war against moral liability to attack on the part of those people not responsible for that wrong). If, targeted for attack. The basis for liability is moreover, war could be expected to prevent moral responsibility for a wrong that bel- or correct wrongs that are insufficiently ligerent action would either prevent or serious to make those responsible for them somehow rectify. The substantive compo- liable to killing or maiming, it seems that nent of the account specifies the types of those good effects must also be excluded wrong that may permissibly be prevented or from the proportionality calculation. One corrected by means of war—namely, wrongs argument for this claim invites us to sup- that are sufficiently serious to make those pose, to the contrary, that good effects of responsible for them liable to be killed or this sort—that is, the prevention or correc- maimed, if necessary, in order to prevent or tion of wrongs that do not rise to the level correct them. of just cause for war—could figure in the To see that only the prevention or cor- proportionality calculation and thus con- rection of wrongs can weigh against the tribute to the justification for the war. Sup- of war in the proportionality calcu- pose, for example, that the prevention or lation, consider what would follow if alleviation of certain forms of religious other desirable goals were allowed to oppression, such as coercing women to count as well. I am assuming that people wear veils, cannot be a just cause for war. can become morally liable to be killed or Yet suppose there is a just cause for war maimed only by virtue of action (which I against a certain country, and that going to take to include knowingly allowing things war against that country could be expected to happen) that wrongs or threatens to also to mitigate the harshness of the reli- wrong others. If that is right and we gious oppression that many of its citizens assume that desirable goals unconnected suffer. It may seem that the expectation of with the prevention or correction of alleviating religious oppression could con- wrongs can count in the proportionality tribute to the justification for war by calculation, it follows that the achieve- weighing against the bad effects in the pro- ment of these goals could justify (or con- portionality calculation, at least if those tribute to the justification for) warred against were responsible for the deliberately killing or maiming innocent oppression. But this seems to imply that the (that is, nonliable) people. Although I pursuit of an end that is insufficient to jus- have conceded that this may be true in tify killing and maiming—namely, alleviat- extreme cases in which the alternative to ing religious oppression— can contribute killing the innocent would be a catastro- to the justification for an activity—war— phe involving substantially greater harm that necessarily involves killing and maim- to the innocent, I have also claimed that a ing. And that makes no sense. It seems, war fought in this way would not be a just war. therefore, that the only ends that can weigh

18 Jeff McMahan against the bad effects of war in the propor- CAN MORE THAN ONE tionality calculation are those specified by BELLIGERENT HAVE A JUST CAUSE? the just cause or causes for war. There is, however, a forceful challenge to I noted in the introduction that the received this argument. Not all of the bad effects of view in international law and contemporary war involve killing or maiming. There are just war theory is that the only just cause for many lesser types of bad effect. Even if the war is defense against aggression. This is relief or mitigation of minor religious pleasing to orthodox theorists because it oppression cannot justify killing or maim- coheres well with the traditional view that at ing, perhaps it can weigh against, and there- most one side in a war can have a just fore justify, the infliction of some of the cause.28 But if, as I have argued, there are lesser bad effects of war. If that is so, per- more just causes than defense against haps certain expected good effects that do aggression, and if, as seems obvious, a coun- not rise to the level of just cause can count try can pursue both just and unjust causes in in the proportionality calculation, provided the same war, then it is clearly possible for that they are weighed only against lesser both sides in a war to have a just cause. expected harms and not against the Here is what I take to be a clear case in inevitable killing and maiming. Only those which two opposing belligerents both have a goods specified by a just cause can be just cause. A and B both plot to conquer ter- weighed against the killing and maiming. ritory belonging to the other.A seizes a piece If good effects beneath the threshold of of B’s territory and B seizes a piece of A’s ter- just cause can weigh only against the lesser ritory—not as a but in accordance bad effects of war, it follows that in certain with plans formulated in advance. Both are cases some such effects cannot count at all. pursuing unjust causes, but each side’s If, for example, a war would have twice as unjust cause gives the other a just cause: many good effects beneath the level of just namely, self-defense or the recovery of cap- cause as it would have lesser bad effects, half tured territory. But neither is simultane- the good effects would count in canceling ously fighting two wars, one of aggression out the bad, but the other half would have and another of defense; rather, each is fight- no justificatory role at all. ing one war on two fronts. Each has the aim This understanding of the proportional- of defeating the other militarily, thereby ity calculation may, however, require com- parisons of expected effects that are too fine-grained to be possible. It seems unreal- 28 In answering the question “whether war can be just istic to suppose that we could separate both on both sides,”Vitoria writes that “except in ignorance, it is clear that this cannot happen.” The exception he the good and bad expected effects of war makes for ignorance is a mistake. After correctly noting into two categories and compare the that “invincible error is a valid excuse,” he then con- expected effects in one category only with cludes that those who fight in good faith, erroneously the expected effects in the corresponding believing their cause to be just, are justified in fighting. But excuse excludes rather than entails justification. category. So assuming that this challenge to (Vitoria, “On the Law of War,” pp. 312–13.) Vattel too the claim that only goods specified by a just asserts that “war cannot be just on both sides,”but says, cause can count in the proportionality cal- more plausibly, of a party fighting an unjust war, that “if he acts in consequence of invincible ignorance or error, culation is correct, its practical significance the injustice of his arms is not imputable to him.”(Vat- may be negligible. tel, The Law of Nations,p.306.) just cause for war 19 enabling itself to reclaim its own territory, But the plausible idea that neither side but also to annex the coveted part of the may be absolutely right and the other other’s territory. absolutely wrong—the idea that both sides This kind of example forces us to recon- may have legitimate claims and griev- sider what might be meant by the assertion ances—does not belong in our conception that a war as a whole is either just or of just cause. Certainly both sides in a war unjust. For what this case shows is that at may have legitimate complaints and griev- least in some instances a war may have ele- ances. But to suppose that just cause is com- ments or phases that are just even though pounded out of all these elements is to other elements or phases are unjust. It is presuppose an overly broad conception of not clear how these can be aggregated to just cause. yield an overall judgment of a war as a Compare individual self-defense. Prior to whole. One coherent question is, of course, a conflict, both parties may have legitimate whether the war is such that it is better that grievances or claims and each may be guilty it be fought than not. But that question, of wrongful provocations. But this is com- even if we take account of considerations patible with one having a right of self- of in answering it, is not equivalent defense and the other having no right at all to the question of whether the war as a in the conflict—for example, if one party whole is just. unjustifiably succumbs to provocation and attacks the other as a means of resolving “COMPARATIVE JUSTICE” their disputes. It is the single act of aggres- sion that makes the aggressor liable and The idea that both sides in a war may simul- gives the defender a right of self-defense. taneously or sequentially pursue both just The same may be true in war. and unjust causes is different from the view of the U.S. Catholic Bishops that both oppo- THE PLURALITY OF CAUSES AND nents in a war may have some degree of jus- THE MORAL STATUS OF tice on their side, and that just cause is COMBATANTS therefore a matter of “comparative” rather than absolute justice. On their view, just There are many cases in which one side in a cause is a matter of “the comparative justice war has no just cause at all. All of its war of the positions of the respective adversaries aims are unjust. There are also cases in or enemies. In essence: Which side is suffi- which one side in a war has one or more just ciently ‘right’ in a dispute...?”29 A similar causes but still ought not to be fighting at though more carefully worked out view is all—for example, because its war is dispro- advanced by A. J. Coates. He argues that portionate, or because it is simultaneously both sides can have just cause (what he calls pursuing a larger unjust cause that all its acts “bilateral justice”), though it may be that of war tend to advance. It is also possible that only one is justified in fighting. “Though a country may have a just cause or set of just never absolute or unilateral, there may be such a preponderance of justice on one side 29 and injustice on the other as to constitute The Pastoral Letter of the U.S. Catholic Bishops, The Challenge of Peace (London: CTS/SPCK, 1983), p. 27. just cause, and even sufficient perhaps to 30 A. J. Coates, The Ethics of War (Manchester, U.K.: 30 justify recourse to war.” Manchester University Press, 1997), p. 151.

20 Jeff McMahan causes sufficient to justify its being at war, soldiers on one side have a just cause while all but that this country also and simultane- those on the other side do not. ously pursues other aims—either aims that One thing we can say is that those who are laudable but inappropriate for pursuit by fight in a war that is unjust overall might be means of war or aims that are positively morally liable to attack even at a time when unjust. These cases, which may even consti- they are pursuing a just cause, because they tute the great majority of cases in which we will soon revert to the pursuit of the larger have been inclined to judge that a war was unjust cause or causes that give the war its just overall, pose a number of problems. I overall status as unjust. When they are pur- will close by mentioning just one of the suing a just cause they are nevertheless at the problems that I think is particularly impor- time engaged in fighting an unjust war—just tant. Recall that I argued earlier that a sol- as they are while they are asleep. dier’s moral status and what he may There is a great deal more to be said about permissibly do—his immunities and this vexed set of issues, but here is not the place rights—both depend on whether he has a to try to say it. I hope, however, to have just cause. The problem is that one and the advanced and defended a conception of just same soldier may at one time act to serve a cause for war that ties it closely to an adver- just cause but at another act to serve an sary’s liability to attack as a result of a wrong unjust cause, and may not himself even for which that adversary is or, in the absence of know which is which. Or it may well be that defensive action, would be responsible. I have a single act by this one soldier will serve both tried to show that this conception, which has a just and an unjust cause. deep roots in the work of classical theorists in In these cases, what is that soldier’s status? the just war tradition but is in many ways anti- Is he liable to attack when his action serves an thetical to contemporary just war theory, has unjust cause but not when it advances a just radical implications for our thinking about the cause? And what presumptions are soldiers morality of war. I hope to explore these impli- on the other side entitled to act on, given that cations further in future work.31 in practice they cannot have knowledge about whether a particular adversary’s action 31 Most comprehensively in a book called The Ethics of supports a just or unjust cause? Matters Killing: Self-Defense, War, and Punishment (New York: would be clearer if we could assume that all Oxford University Press, forthcoming).

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