Kant and the Law of War
ARTHUR RIPSTEIN
University of Toronto
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Names: Ripstein, Arthur, author.
Title: Kant and the law of war / Arthur Ripstein.
Description: New York, NY : Oxford University Press, [2021] | Includes bibliographical references and index.
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Subjects: LCSH: War—Moral and ethical aspects. | War (Philosophy) | Kant, Immanuel, 1724–1804.
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To the memory of my parents, who knew war too well: Reginald Ripstein, 1909–2004 patriot and soldier
Ellen Ripstein, 1922–2013 refugee and spy
7.
8.
Acknowledgments
I have been working on this project for many years and have benefited from the generosity of many people and many institutions. I discussed the right of nations only briefly in my 2009 book, Force and Freedom. I realized I had to give the matter much more thought when the late Ruth Gavison served as my commentator at a 2010 conference celebrating the work of Barbara Herman. I was not fully satisfied with my response to one of her objections; I hope this book provides a more adequate response. Around the same time, Karen Knop convinced me to comment on a lecture on the Salamanca scholastics, deepening my understanding of Kant’s disdain for the just war tradition.
Material included in this book was presented at universities in Europe, North America, Argentina, and Israel. I am grateful to members of those audiences for their comments and questions, and to Haim Abraham, Arthur Applbaum, Sorin Baiasu, Gabriela Blum, Matthew Braham, Jutta Brunnée, Patrick Capps, Georg Cavallar, Alejandro Chehtman, Joshua Cohen, Hanoch Dagan, Steve Darwall, Jeremy Davis, Yasmin Dawood, Avihay Dorfman, David Dyzenhaus, David Enoch, Chris Essert, Ruth Gavison, Ido Geiger, Maytal Gilboa, Micha Gläser, John Goldberg, Javier Habib, Martín Hevia, Louis-Philippe Hodgson, Kinch Hoekstra, Jakob Huber, Tom Hurka, Edward Iacobucci, Shelly Kagan, Frances Kamm, Larissa Katz, Michael Kessler, Pauline Kleingeld, Dennis Klimchuk, Karen Knop, Nico Kolodny, Mattias Kumm, Christopher Kutz, Joanna Langille, Arthur Lau, Thomas Lee, Sylvie Loriaux, Reidar Maliks, Macarena Marey, Avishai Margalit, Christopher Meckstroth, Naz Modirzadeh, Saira Mohamed, Sofie Møller, Sankar Muthu, Marie Newhouse, Cara Nine, Kristi Olson, Jennifer Page, Japa Pallikkathayil, Herlinde Pauer-Studer, Jonathan Quong, Leonard Randall, Mathias Risse, Michal Saliternik, Douglas Sanderson, Tim Scanlon, Tamar Schapiro, Rudolf Schüssler, Daniel Schwartz, Konstanze von Schütz, Camilla Serck-Hanssen, Ayelet Shachar, Scott Shapiro, Stephen Smith, Horacio Spector, Gopal Sreenivasan, Nick Stang, Daniel Statman, Hamish Stewart, Martin Stone, Sergio Tenenbaum, Elad Uzan, Helga Varden, Nina Varsava, Emmanuel Voyiakis, Jay Wallace, Ernest Weinrib, Jacob Weinrib,
Howard Williams, Reed Winegar, Allen Wood, Rega Wood, Ewa WyrębskaĐermanović, Gideon Yaffe, Jonathan Yovel, Lea Ypi, Yuan Yuan, Katja Ziegler, Ben Zipursky, Reif Zreik, Ariel Zylberman, and two anonymous referees for Oxford University Press for comments and discussion. Manula Adhihetty, Michael Law-Smith, Manish Oza, Benjamin Zolf, and Andy Yu provided excellent research assistance. Jamie Berezin, my editor at Oxford University Press, supported the project from the start.
In addition to all of these debts, I owe additional thanks to Ester HerlinKarnell and Enzo Rossi for organizing two workshops in Amsterdam and for editing a book, The Public Uses of Coercion and Force: From Constitutionalism to War, on an earlier version of the manuscript, as well as to the contributors to that book: Yitzakh Benbaji, Luigi Corrias, Katrin Flikschuh, Rainer Forst, Aravind Ganesh, Alon Harel, Ester Herlin-Karnell, Thomas Mertens, Peter Niesen, Johan Oltsthoorn, Alice Pinheiro Walla, Massimo Renzo, Anna Stilz, Malcolm Thorburn, and Bertjan Wolthuis, many of whom also gave additional comments on the manuscript. Although I continued revising the manuscript in the time that they were writing their comments, I have avoided, where possible, including any revisions that preempt their comments and objections.
I am grateful to Jay Wallace and the other members of the Berkeley Tanner Lectures Committee for inviting me to give the 2019 lectures, to my commentators, Oona Hathaway, Christopher Kutz, and Jeff McMahan, for their engaging and exacting commentaries, and especially to Saira Mohamed, who edited the volume on them, Rules for Wrongdoers.
I also thank George Pavlakos and Christian Tams for organizing a workshop in Glasgow on a later version of the complete manuscript, at which helpful comments were presented by Annabel Brett, Tria Gkouvas, PhilippAlexander Hirsch, George Pavlakos, Charlene Peevers, Christian Tams, and Alain Zysset.
The Faculty of Law and Department of Philosophy at the University of Toronto provided an ideal setting to work on this project. I give thanks to Ed Iacobucci, who was Dean of Law during the time I was working on this project, and to Martin Pickavé, who was Chair of the Philosophy Department during the good part of that time, both of whom provided unfailing support. Toronto may be the only place in the world where a dozen or so faculty members will show up weekly, decade in and decade out, to discuss old books on legal and political philosophy. Members of the Toronto law and philosophy discussion group, regulars, visitors, and more recently, online
participants, came to my office weekly for eight years of Kant, three and a half years of Grotius, a year of Suárez, and two years of Pufendorf, and then spent an additional fifteen weeks working through the manuscript with me. While working on this book, I learned much from the students whose doctoral dissertations I supervised: Haim Abraham, Lu-Vada Dunford, and Joanna Langille.
I had the good fortune to work on this project in a period of growing interest in Kant’s legal and political philosophy and in his views about international right. My views have developed through studying the views of, and conversations with, many people. I have benefitted especially from engagement with the groundbreaking work of Katrin Flikschuh, Pauline Kleingeld, and Anna Stilz.
I am also grateful to the Social Science and Humanities Research Council of Canada for Grant 435-2014-0306 in support of this project and to the Canada Council for the Arts for a Killam Research Fellowship that released me from teaching and administrative duties to work on it.
My wife, Karen Weisman, and our children, Aviva and Noah, provided constant stimulation and support.
My late parents did not live to see this book, but their memory was pervasive as I worked on it. They had direct experience of war, figuring in some of the key roles discussed in this book. Committed to fighting aggression, my father, Reginald, enlisted in the Canadian army at the age of thirty-one. Too old to be sent to the front, he taught ballistics in Canada and Britain. My mother, Ellen, fled Germany in 1935 to the apparent safety of Amsterdam— the only place that would admit German Jews at the time. She was seventeen when the Netherlands was invaded. In 1943, her parents were deported and murdered, her mother in Auschwitz and her father in Sobibor. My mother survived the war through the protection of the Herrndorf family and sheer nerve. She served in the Dutch underground, smuggling documents and sometimes weapons. Her blond hair, blue eyes, and perfectly accented German enabled her to calmly talk her way past murderous guards. After the war, she was a stateless refugee. The Herrndorf family were given immigrant visas to Canada. My mother’s application was denied. Stanley Knowles, the CCF member of Parliament for Winnipeg North Centre, learned of her situation and called a senior official in the department of immigration. He was told that Canada did not want more of “those people.” Knowles told the official that he would quote him in Parliament during question period the next day. Within an hour, the visa was slipped under his door. I dedicate this book
to the memory of my parents, in the hope that their grandchildren will live in a peaceful world.
Earlier versions of some of the material included in this book has appeared elsewhere:
• An earlier version of parts of Chapter 1 appeared in Kant Studien Band 107 Heft 1 (2016).
• An earlier version of parts of Chapter 2 appeared in Kantian Review, vol. 24, no. 3 (2019).
• An earlier and much condensed version of some material interspersed throughout Chapters 4, 5, and 6 appeared in Arthur Ripstein, Rules for Wrongdoers: Law, Morality, War (Saira Mohammad ed., Oxford: Oxford University Press, 2021). The Berkeley Tanner Lectures book series aims to reproduce as far as possible the live events that provide their basis. That occasion was directed to an audience with limited familiarity with or interest in Kant, so that the presentation engages much less with the specifics of the Kantian texts and the relation between war and the broader structure of public right. The present text also reflects much that I learned from the responses to the lectures, in particular, avoiding several formulations that I now recognize to have been potentially misleading.
• An earlier version of some material included in Chapter 8 appeared in Katrin Flikschuh and Lea Ypi (eds.), Kant and Colonialism: Historical and Critical Perspectives (Oxford: Oxford University Press, 2014).
• Some material included in Chapter 9 revisits issues introduced in “Bringing Rights and Citizenship under Law on a Globus Terraqueus,” in Camilla Serck-Hansen et al. (eds.), Proceedings of the 13th International Kant Congress (Berlin: De Gruyter, 2021).
A note on references to Kant: All references to Kant are cited by their Prussian academy pagination. Unless otherwise indicated, the translations are taken from the Cambridge Edition of the Works of Immanuel Kant, edited by Paul Guyer and Allan Wood, particularly the volume, Practical Philosophy (Mary Gregor ed. and trans., Cambridge: Cambridge University
Press, 1996). Because the Gregor translation of the Doctrine of Right is available in multiple editions and paginations, all references are to the Prussian Academy pagination appearing in the margins. References to the Doctrine of Right are by Academy pagination only; other works are cited by title and Academy pagination.
Perpetual War or Perpetual Peace
I. Introduction
Kant’s Doctrine of Right concludes with the claim that “morally practical reason pronounces an irresistible veto: there is to be no war, neither war between you and me in the state of nature nor war between us as states, which, although they are internally in a lawful condition, are still externally (in relation to one another) in a lawless condition; for war is not the way in which everyone should seek his rights.” Kant continues, “a universal and lasting peace constitutes not merely a part of the doctrine of right but rather the entire final end of the doctrine of right within the limits of mere reason; for the condition of peace is alone that condition in which what is mine and what is yours for a multitude of human beings is secured under laws living in proximity to one another.”1
Kant elsewhere characterizes war as the “barbaric way (the way of savages)”2 of deciding disputes. “Barbarism” is a technical term for Kant; in the Anthropology, he defines it as “force without freedom or law.”3 Barbarism is the condition in which force alone decides how things stand between human beings. In such a condition, one party is entirely subject to the private choice of another; which one prevails depends only on their comparative power. To remain in such a condition is therefore “wrong in the highest degree”4 because it is inconsistent with rightful relations in which free beings are independent of each other.
War has a distinctive morality because of this distinctive immorality. Kant’s opposition to war is paired with a discussion of right in war, with respect to going to war, the conduct of war, and the behavior of the victorious party after a war. My aim in this introductory chapter is to explain how Kant
1 The Doctrine of Right, 6:355.
2 6:351.
3 Kant, Anthropology from a Pragmatic Point of View (Robert Louden trans., Cambridge: Cambridge University Press, 2006), 7:330.
4 6:307.
can have a conception of right in war, against the background of his more general view that war is by its nature barbaric and to be repudiated entirely. I will introduce Kant’s organizing idea that peace is a positive moral idea, an idea that is inseparable from a family of ideas about the moral significance of a legal order. These ideas provide a compelling account of the moral and legal principles governing the initiation, conduct, and conclusion of war. The organizing thought is simple, though its implications are sometimes complex: the very thing that makes war wrongful, that is, the fact that, as Kant puts it, “it hands everything over to savage violence,” actually provides the basis for norms governing each of its initiation, its conduct, and its conclusion.
The basic norm governing initiating war is a straightforward prohibition of aggressive war. Resort to force is only acceptable when defensive. The norms governing the conduct of war restrict the means that can be used in war to ones that are consistent with the possibility of a future peace; these restrictions apply to both sides in a war, because the requirement to act in a way that is consistent with the possibility of a future peace applies in the same way to defender and aggressor alike. The norms governing what happens after war are also driven by the demands of peace. So, too, are the requirements for creating public international legal institutions. These norms governing the initiation, conduct, and results of war are merely preliminary to the possibility of a “universal and lasting peace,” which is why Kant characterizes those norms as “Preliminary Articles for Perpetual Peace.” Conformity with them would be sufficient to mark a transition from a state of barbarism, in which force (or its prospect) decides everything, to a state of anarchy, in which nations do not in fact resort to war but still lack common institutions. A condition of anarchy is empirically more peaceful than a condition of war, but it is unstable, because it depends on the particular choices made by particular nations.5 As important as those articles are in reducing the temptations of war, they are not sufficient for peace. The further transition to a condition of peace requires what Kant characterizes as “Definitive Articles” for Perpetual Peace—the creation of institutions through which the principle of freedom under law applies to every human interaction, both between individual human beings, between each person and the nations of which that person is a member, between nations, and between individual human beings and nations of which they are not members.
5 Hobbes marks this same distinction in Chapter 13 of Leviathan when he describes war as the condition “wherein the Will to contend by Battell is sufficiently known,” but then notes that war includes “all the time there is no assurance to the contrary.”
Kant’s conception of right in war is distinctively legal. He understands law to be the alternative to war and identifies a condition of peace as one in which interaction is governed by law. Conversely, his account of legality is distinctively moral, and comes out of a broader view of what it is for free human beings to interact with each other on terms consistent with the freedom of everyone. The demands of interpersonal morality can only be properly realized under a public legal order. The moral requirements of a public legal order, in turn, dictate the way in which nations may rightfully interact with each other, culminating in the prohibition of aggressive war and limitations on the ways in which a war (whether justified or not) may be fought. This idea of the priority of peace therefore understands questions about the morality of war and questions about its legality as inseparable. The idea that there could be a distinctive conception of war, at once both moral and legal, is Kant’s fundamental contribution to the study of peace and war. The purpose of this book is to fill out that overlooked contribution.6
Kant has been claimed as a champion by almost every view about the moral status of war.7 He is sometimes claimed, other times criticized, as a kind of naïve moralist, urging restraint in war, as if doing so was the most promising strategy to hasten the coming of peace. Some have sought to situate (sometimes to discredit) his views of war as aspects of a comprehensive, if outdated, philosophy of history. Other, more recent, readings have reacted against this naïve pacifist reading and made him out to be a hardnosed realist8 and, on still another cluster of accounts, a champion of “regime change” so as to spread democracy.9 On another familiar view, he is heir to
6 The great international lawyer Hersch Lauterpacht endorsed a version of Kant’s position (although without reference to Kant) in the closing pages of his 1933 book, The Function of Law in the International Community, when he wrote: “For peace is not only a moral idea. In a sense (although only in one sense) the idea of peace is morally indifferent, inasmuch as it may involve the sacrifice of justice on the altar of stability and security. Peace is pre-eminently a legal postulate. Juridically it is a metaphor for the postulate of the unity of the legal system. Juridical logic inevitably leads to condemnation, as a matter of law, of anarchy and private force.” Hersch Lauterpacht, Function of Law in the International Community (Oxford: Clarendon Press, 1933), 438.
7 Allen Wood’s remark that “[t]he views people attribute to Kant on religion often tell you far more about those people than they do about Kant” has a parallel here. See Allen W. Wood, Kant and Religion (Cambridge: Cambridge University Press, 2020), xv.
8 Richard Tuck, “The Hobbesianism of Kant,” in his Rights of War and Peace (Cambridge: Cambridge University Press, 2001); Kenneth Waltz, “Introduction,” “Kant, Liberalism and War,” and “Structural Realism after the Cold War,” in his Realism and International Politics (New York: Routledge, 1998); William E. Scheuerman, “Realism and the Kantian Tradition: A Revisionist Account,” International Relations 26(4), (2012), 453–477.
9 Susan Meld Shell, “Kant on Just War and ‘Unjust Enemies’: Reflections on a ‘Pleonasm,’” Kantian Review 10 (2005), 82–111. See Georg Cavallar’s reply, “Commentary on Susan Meld Shell’s ‘Kant on Just War and ‘Unjust Enemies’: Reflections on a ‘Pleonasm,’” Kantian Review, 11 (2006), 117–124; Fernando Téson, “The Kantian Theory of International Law,” Columbia Law Review 92(1) (January
a tradition of thinking about justice in war that flows more or less continuously from Augustine and Aquinas through Grotius and Vattel. On still other readings, he is a precursor of modern social science, putting forward a bold (and at the time completely unsubstantiated) “democratic peace hypothesis,” according to which democracies do not go to war with each other.10 Some assert that this view commits Kant to licensing democracies to wage war against non-democracies.11
I will offer an alternative to these readings, situating Kant’s theory of war in his views about the nature of public law. In order to do so, I will draw on, without developing in full detail, several broad themes from Kantian legal and political philosophy. The Doctrine of Right is the first part of Kant’s Metaphysics of Morals, which he presents as an a priori inquiry, independent of empirical inquiries and questions of virtue. Some of Kant’s factual claims, including some that show up in his examples, are hopelessly mistaken; others (especially, prior to the 1790s, about differences between races,12 and throughout his life about the abilities of women13) are both hopelessly mistaken and morally outrageous. These claims are in no way excused by the fact that Kant drew on what he often recognized to be the unreliable reports of travelers of his day.14 That reliance does show that he had no special gifts as a social scientist, and more generally, that the application of concepts of
1992), 53–102; Roger Scruton, “Immanuel Kant and the Iraq War,” https://www.opendemocracy.net/ en/article_1749jsp/. See the reply by Antje Vollmer, “Immanuel Kant and Iraq: A Reply to Roger Scruton” (April 2004), https://www.opendemocracy.net/globalization-iraqwarphiloshophy/article_ 1821.jsp#comments1
10 Michael Doyle, “Kant, Liberal Legacies, and Foreign Affairs,” Philosophy & Public Affairs 12(3) (Summer 1983), 205–235. And “Kant, Liberal Legacies, and Foreign Affairs, Part 2,” Philosophy & Public Affairs 12(4) (Autumn 1983), 323–353. For a contrasting reading, see also Georg Cavallar, “Kantian Perspectives on Democratic Peace: Alternatives to Doyle,” Review of International Studies 27(2) (April 2001), 229–248.
11 See, e.g., Anthony Angie, Imperialism, Sovereignty and the Making of International Law (Cambridge: Cambridge University Press, 2005), 295–296. Angie somehow concludes from Kant’s claim in Toward Perpetual Peace that individual human beings and nations do wrong by remaining in a nonlegal condition that Kant must therefore suppose that those who are in a legal condition are entitled to use force against those who are not, a claim that Kant explicitly denies in both Toward Perpetual Peace and the Doctrine of Right. In support of his reading, Angie does not refer to Kant or Kantians, instead, he quotes claims made by Ann-Marie Slaughter. Although Slaughter mentions Doyle’s attribution of the “democratic peace hypothesis” to Kant in several footnotes of the piece Angie cites, she does not refer to Kant or claim to be making Kant’s argument or even a Kantian one.
12 See the discussion in Pauline Kleingeld, “Kant’s Second thoughts on Race,” The Philosophical Quarterly 57(229) (2007), 573–592, and Lucy Allais, “Kant’s Racism,” Philosophical Papers 45(1–2) (2016), 1–36.
13 See Pauline Kleingeld, “The Problematic Status of Gender-Neutral Language in the History of Philosophy: The Case of Kant,” The Philosophical Forum XXV(2) (1993), 134–150.
14 Oliver Eberl, “Kant on Race and Barbarism: Towards a More Complex View on Racism and Anti-Colonialism in Kant,” Kantian Review 24(3) (2019), 385–413.
right to empirical particulars is, as Kant argues, dependent both on facts and the exercise of judgment. In what follows, I take seriously Kant’s claim that the Doctrine of Right provides a metaphysics rather than an anthropology of morals, looking at his arguments and their presuppositions and implications.
II. Just War, Regular War, and Perpetual Peace
Kant develops his account of war against the background of two contending and sometimes competing approaches to it in the history of philosophy. These two approaches share a common moral and legal vocabulary, but differ in their animating conceptions and the legal metaphors through which they articulate them. The groupings mask important areas of overlap, but we can think of each of them as an ideal type, each of which organizes its understanding of war in terms of a familiar legal relationship.
One of these, usually described as the just war tradition, begins in Augustine and Aquinas, and reaches its fullest articulation in the work of the Salamanca scholastics, especially Francisco de Vitoria and Francisco Suárez. It understands war as a sort of enforcement action and focuses on the justice of the cause for the sake of which the war is initiated. Because they regarded war as essentially an enforcement action, these writers articulated a list of “just war conditions,”15 each of which was necessary in order for the conduct of the war to be just; in addition to a catalog of just grounds for war, those lists included not only such factors as the necessity of going to war and the prospect of success but, no less significantly, factors that are specific to the justice of punishment, including not only the guilt of the party to be punished and the requirement that the punishment be carried out with proper authority and with the right intention, but also that it be proportionate to the seriousness of the wrong.
Just war writers did not always agree among themselves, and some members of the “second scholastic,” such as Melchor Cano, were harshly critical of others, including Vitoria, especially concerning the Spanish conquest of the Americans.16 Despite these differences, they shared an organizing set
15 For a standard list, see James Turner Johnson, Just War Tradition and the Restraint of War: A Moral and Historical Inquiry (Princeton: Princeton University Press, 1981).
16 See the discussion by Anthony Pagden, “Defending Empire: The School of Salamanca and the ‘Affair of the Indies,’ ” in The Burdens of Empire: 1539 to the Present (Cambridge: Cambridge University Press, 2015), 45–74. Pagden points out that Melchor Cano rejected the claim that the Spaniards could claim the rights of travelers when conquest was the purpose of their travels, and argued that even if the inhabitants were like children, incapable of ruling themselves, others were
of ideas, the most significant of which was the idea, no longer familiar, that the basic ground for going to war was backward looking, either in the form of punishment or of reclaiming something wrongfully taken. Just war writers view a state engaged in war as prosecutor, judge, and executioner, competent to address both past and prospective wrongdoing. Augustine distinguishes offensive from defensive wars and makes the former his main focus; Suárez concentrates primarily on offensive wars, noting almost in passing that the rationale for fighting them also justifies defensive force.17 Augustine and Aquinas defended remedial and punitive wars; Suárez added what may look to the modern reader like claims to distributive justice18 to the list of grounds of war, defending the Spanish conquest of the Americas on the grounds that the Indigenous inhabitants were likely to resist settlers and missionaries and therefore deny people access to their just shares of the earth’s resources.19
These just war writers articulated the familiar thought that in war it very much matters who is in the right. They concluded from this that in war at most one side could be in the right, although the other might be excused through what Vitoria described as “invincible error.”20 For these writers, all of the rules governing the conduct of war are rules for restraining the ways in which those with a just case could prosecute it. In his description of what he called the “natural law of nations,” the seventeenth-century German not entitled to use force because their duty to protect was a duty of charity. Annabel Brett, “Scholastic Political Thought and the Modern Concept of the State,” in A. Brett and J. Tully, and H. HamiltonBleakley, (eds.) Rethinking The Foundations of Modern Political Thought (Cambridge: Cambridge University Press), 130–148, draws attention to Melchor Cano’s appeal to the analogy between wars among European states and colonial conquest.
17 Suárez writes “we have to consider whether the injustice is, practically speaking, simply about to take place; or whether it has already done so, and redress is sought through war. In this second case, the war is aggressive.” Francisco Suárez, “Disputation XIII: On War,” in Selections from Three Works of Francisco Suárez (Gwladys L. Williams, Ammi Brown, and John Waldron trans., Oxford: Clarendon Press, 1944), 802, ¶ 5.
18 The scholastic writers represented the refusal of the Indigenous inhabitants of the Americas to yield land to Spanish settlers as an instance of what Aquinas called “communitive justice,” because the contended that doing so interfered with the settlers’ right to underutilized land, rather than a claim in distributive justice to a specific share of the earth’s land or fruits.
19 Francisco Suárez (De Fide, disp. 18, sec. 1, n. 9 (vol. 5, 440]). Suárez restricts this to occasions on which the infidel prince has first been asked to allow missionaries in. Francisco Suárez, Selections from Three Works, supra note 17, at 748. “But if the unbelieving princes resist, and do not grant entrance, then, in my opinion and on account of the reasons given above, they may be coerced by the sending of preachers accompanied by an adequate army.” See the discussion in John P. Doyle, “Francisco Suárez: On Preaching the Gospel to People Like the American Indians,” Fordham International Law Journal 15 (1991), 879. See also Francisco de Vitoria, “On the American Indians,” 1. Conclusion, in Vitoria, Political Writings (A. Pagden and J. Lawrence eds., Cambridge: Cambridge University Press, 1991), 250.
20 Vitoria, Political Writings, supra note 19, at 313.
rationalist writer Christian Wolff wrote, “He who wages an unjust war has no right in war, and all his force is illegal.”21 For the just war tradition, then, war is a unilateral act designed to right or prevent a wrong. Versions of the just war approach structure most contemporary moral discussions of war. Recent writers in this tradition have questioned the familiar idea that combatants on both sides of the war are subject to the same moral restrictions, arguing that those who lack a just cause are not permitted to use any form of force.22
The other important strand in Western thought about war (sometimes described as the “regular war” tradition)23 was developed by writers often described as the founders of international law: Grotius, Pufendorf, and Vattel.24 Kant characterized these three as “miserable comforters [leidige Tröster],” because they had an even more expansive conception of the acceptable grounds of going to war than did the earlier just war writers.25 Grotius argued that a sovereign may resort to war if no court is available, or if it is not satisfied that an available court will deliver the correct verdict. Vattel explicitly compares battles to legal proceedings and describes war as a legitimate
21 “Quamobrem qui bellum injustum gerit, ei jus nullum in bello.” Christian Wolff, Jus Gentium Methodo Scientifica (Frankfurt and Leipzig: Societas Veneta, 1764), 777; for the English translation, see Christian Wolff, Jus Gentium Methodo Scientifica (Joseph H. Drake trans., Oxford: Clarendon Press, 1934), 2:402.
22 Jeff McMahan, Killing in War (Oxford: Oxford University Press, 2009).
23 Peter Haggenmacher, “Just War and Regular War in Sixteenth Century Spanish Doctrine,” International Review of the Red Cross 32 (1992), 434–445, attributes this term to Maurice Bourquin, “Grotius est-il le pere du droit des gens?,” in Grandes figures et grandes a’uvres juridiques (Geneva: Memoires publies par la faculte de droit de l’Universite de Geneve, No. 6, 1948), 77–95. Haggenmacher develops his reading of Grotius in detail in his Grotius et la doctrine de la guerre juste (Paris: Presses Universitaires de France, 1983), esp. Ch. 6: “Les limites formelles du droit de guerre: le problème des effets de la guerre publique solennelle et le “ius in bello” classique,” at 568–612. Whewell sometimes translates Grotius’s solenne as “formal” and other times as “regular.” Drawing on Haggenmacher, Gregory Reichberg compares the two in “Just War and Regular War: Competing Paradigms,” in David Rodin and Henry Shue, Just and Unjust Warriors (Oxford: Oxford University Press, 2008), 193–213. Stephen C. Neff refers to Vattel’s approach as “War in Due Form,” a term he takes from Vattel. Stephen C. Neff, War and the Law of Nations (Cambridge: Cambridge University Press, 2005), 95. See also Carl Schmitt’s defense of what he calls the “non-discriminating” conception of war, based on the claim that any alternative will turn every war into a “crusade.” Carl Schmitt, Der Nomos der Erde im Völkerrecht des Jus Publicum Europaeum (1950), translated in The Nomos of the Earth in the International Law of the Jus Publicum Europaeum (G.L. Ulmen trans., Telos Press, 2003).
24 E.g., Suárez, Disp. XIII: On War in Selections, supra note 17, at 851, almost states the regular war position when he writes that a war fought by agreements of both sides is unjust in the eyes of God but gives rise to just effects.
25 Immanuel Kant, Toward Perpetual Peace, translated by Mary Gregor in Kant, Practical Philosophy (Cambridge: Cambridge University Press, 1996), 326 (8:355). Like Eliphaz, Bildad, and Zophar in the Book of Job in the Hebrew Bible, they conclude from any display of force that justice has been done, in so doing “speak as if they are secretly being listened to by the mighty one, over whose cause they are passing judgment, and as if gaining his favor through their judgment were closer to their heart than the truth.” Kant, “On the Miscarriage of all Philosophical Trials in Theodicy,” translated by Allen W. Wood and George Di Giovanni in Religion and Rational Theology (Cambridge: Cambridge University Press, 1996), 33 (8:265).
means of acquisition.26 Where the just war tradition views war as an enforcement action in which a right is enforced against a wrongdoer, Grotius and Vattel view it instead as a mode of dispute resolution.27 No court or procedure has jurisdiction over sovereigns, and when they cannot agree, or agree on a procedure to resolve their dispute, they submit it to what Pufendorf describes as the “dice of Mars.”28
Just as the views of the just war writers was structured by their legal metaphor of the execution of a judgment, so too the views of the regular war writers were structured by theirs of a procedure for dispute resolution. Their central question is whether a war is conducted in accordance with the appropriate procedure; even questions about just cause are framed as questions of whether the party starting the war has what lawyers call a “cause of action,” that is, whether there is a genuine dispute about the respective rights of the two states. If a state had a cause of action, it was entitled to go to war; the procedure of war was supposed to resolve the dispute, and so the authorization to go to war could not depend on knowing who was in the right. Grotius’s The Law of War and Peace29 is explicitly organized on the model of a legal treatise, beginning with a discussion of the nature of war (Book I), then going through the possible grounds of war or causes of action (Book II), before turning to the procedures through which a war is conducted, including both the acceptable moves within those procedures and the legal consequences of that resolution (Book III).
By viewing war as a mode of dispute resolution, early international lawyers had a ready explanation of why the same rules would apply to both sides in a conflict: the dispute arose because neither was under any duty to defer to the other’s judgment about the underlying merits of the dispute. As such, the norms governing it could not track those underlying merits. Wolff referred to this as the “voluntary law of nations,” arguing that the nations of the world had agreed to suspend the “natural law of nations”30 that denied
26 Emerich de Vattel, Le Droit des Gens, ou Principes de loi Naturelle, Appliques à la conduite & aux affaires des Nations & des Souverains, Tome Second 3:74 (Bk. III, Ch. 13, § 193), at 170, London: Chez Benjamin Gibert 1758, translated as The Law of Nations, Or, Principles of the Law of Nature, Applied to the Conduct and Affairs of Nations and Sovereigns, edited and with an Introduction by Béla Kapossy and Richard Whatmore (Indianapolis: Liberty Fund, 2008).
27 See Neff, War and the Law of Nations, supra note 23, esp. Ch. 3, “War in Due Form”; also Schmitt, Nomos of the Earth, supra note 23
28 Samuel Freher von Pufendorf, Two Books of the Elements of Universal Jurisprudence (William Abbott Oldfather trans., Oxford: Clarendon Press, 1931), revised by Thomas Behme (Indianapolis: Liberty Fund, 2009), 57.
29 Hugo Grotius, de iure belli ac pacis 1625, translated by William Whewell, as On the Laws of War and Peace (Cambridge: Cambridge University Press, 1853).
30 Wolff, supra note 21, 2:402.
any right to use force to those lacking a just cause in order to resolve disputes in an orderly manner and minimize the costs and devastation of war. Some of the norms of the voluntary law of nations limited the use of force; others demanded that coerced peace agreements be binding so that it would be possible for wars to end. All of these rules applied to both sides, so as to avoid prejudging the merits of the dispute that the war was supposed to resolve. If you and I agree to resolve a dispute by playing chess, I am in no position to demand that you play without a queen because I am in the right. So too with war, according to these writers.
Both of these positions seek to make moral sense of war; each does so by bringing more general moral and legal ideas to bear on it. The just war tradition insists that war is permissible in order to do justice and, further, that justice must be done in this world. Suárez entertains the objection to a sovereign serving as judge in his own case, only to reject it, concluding,
in the world as a whole, there must exist, in order that the various states may dwell in concord, some power for the punishment of injuries inflicted by one state upon another; and this power is not to be found in any superior, for we assume that these states have no commonly acknowledged superior; therefore, the power in question must reside in the sovereign prince of the injured state, to whom, by reason of that injury, the opposing prince is made subject; and consequently, war of the kind in question has been instituted in place of a tribunal administering just punishment.31
For its part, the regular war tradition insists that it must be possible to give effect to rights if they are to be anything at all. But that means that should a dispute about rights arise, there must be a procedure through which it can be resolved, consistent with the status of both disputants as right holders. Within a state, disputants are required to consult their superior—their sovereign or his magistrates—in order to resolve disputes. When disputes arise between sovereigns, however, no superior is available. If mediation, arbitration, lottery, and battle by individual champions are not acceptable to the parties to a dispute,32 war is available as a last resort. War differs from these
31 “On Charity,” in Suárez, Selections from Three Works, supra note 17, at 818. Compare Vitoria’s remark that “the prince has the authority not only over his own people but also over foreigners to force them to abstain from harming others; this is his right by the law of nations and the authority of the whole world.” Vitoria, Political Writings, supra note 19, at 305.
32 Grotius, Bk. II, Ch. XXXIII, supra note 29, at ss. vii–x (Whewell, 273–277).
alternatives because it is the only procedure for dispute resolution that is selfexecuting: the party that prevails is in a position to guarantee compliance from the vanquished party. There is no empirical or conceptual space between victory in war and the resolution of the conflict. Force alone decides, but its result gives rise to a right on the part of the victor.
The just war approach attracted more philosophical attention in the modern period, but the regular war approach dominated law and international affairs. By the early twentieth century, the widely acknowledged legal, if not moral, position was that going to war was a sovereign prerogative. In the nineteenth century, leading writers about international law supposed that the voluntary law of nations, constituted by the customary conduct and implicit agreement of the nations that regarded each other as “civilized,” displaced any competing background natural law of nations. In the middle of the last century, a leading international lawyer could write an article suggesting justice in going to war was not a legal concept at all.33
Kant is sharply critical of what he calls the “veil of injustice”34 of the just war tradition and the “miserable comforters”35 of the regular war tradition. Kant regards the most prominent scholastic just war writers as disingenuous apologists for European colonialism, and notes that the miserable comforters were always “duly cited” in justifications for aggressive war. Their defenses of such wars were not misapplications of their more general accounts, or even of lax standards within those accounts. The larger problem is that both approaches fail to grasp the fundamental moral problem with war: it resolves matters through force, and so determines results independently of the merits. The just war tradition overlooks this feature of war because its focus on just cause presupposes that the question of who is in the right has already been resolved. The regular war tradition is not bothered by the realization that war is not about the merits, because it regards force as an agreed and therefore acceptable way for sovereigns to resolve their disputes.
Kant’s objection to the legal metaphors that animate both traditions reflects a deeper objection to their conception of a legitimate legal proceeding, whether the enforcement of the judgment or the litigation of a claim. For Kant, any properly legal proceeding must be structured by what he
33 See Arthur Nussbaum, “Just War: A Legal Concept?,” Michigan Law Review 42(3) (December 1943), 453–479.
34 6:266.
35 8:355. He later (implicitly) describes them as “political moralists,” that is, those who “[frame] morals to suit the statesman’s advantage.” 8:372.
calls “the right to be beyond reproach,” the requirement that any wrongdoing be established against the presumption that the accused person has done no wrong. This idea structures the burden of proof in modern legal systems and marks its fundamental distance from older ideas of trial by ordeal, in which the accused person was presumed guilty, and only divine intervention could establish innocence. The just war approach rejects the presumption of innocence in favor of the idea that the aggrieved prince will investigate carefully; the regular war approach favors a “procedure” structured by nothing more than the might of the stronger.
The irresolvable tension between force and right leads Kant to the surprising claim that peace is the central concept in the morality of war. Kant’s solution has two parts: an account of the distinctively public nature of a state, and an account of peace as an essentially public condition under which disputes can be resolved on their merits. War is “wrong in the highest degree” because it “hands everything to savage violence, as if by law.”36 War is the condition in which might makes right; peace is a condition in which, through the establishment of procedures, right guides might. Kant’s characterization of the difference between peace and war is the systematic development of Cicero’s older distinction between two fundamental ways in which human beings might conduct their affairs: through words and through the use of force.37 Kant develops this idea to argue that peace is the condition in which legal institutions and procedures discipline all uses of force. On this Kantian view, a condition of peace is also a condition of law, one in which institutions are in place through which claims can be made and disputes resolved. Public institutions charged with making, applying, and enforcing law determine which norms can be enforced and who can enforce them. In bringing both conduct and enforcement under general and public rules, law limits uses of force to those that are publicly authorized under those rules. In a legal order, force is thereby subordinated to words, because any use of force requires legal authorization. The moral idea of legality and the idea of peace are therefore inseparable. Together they explain what is distinctively wrongful about war: war is on the wrong side of Cicero’s distinction. As Kant observes, “it is difficult even to form a concept of this or to think of law in this lawless state without contradicting oneself.”38 Difficult, but not impossible: leaving
36 6:307.
37 Cicero, De Officiis, translated by Walter Miller as On Duties (Cambridge, MA: Harvard University Press, 1913), 36–37. As Cicero puts it, discussion is proper to humans, force to animals.
38 6:347. In framing the challenge, Kant paraphrases (but does not endorse) Cicero’s pessimistic conclusion, “When arms speak, the laws are silent.” Cicero, Pro Milone. In Cicero, Orations (N.H.
