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Should International Law Ensure the Moral Acceptability of War?



Jeff McMahan's challenge to conventional just-war theory is an attempt to apply to the use of force between states a moral standard whose pertinence to international relations (IR) is decreasingly contestable and the regulation of which international law (IL) is, therefore, under pressure to afford: the preservation of individual rights. This compelling endeavour is at an impasse given the admission of many ethicists that it is currently impossible for international humanitarian law (IHL) to regulate killing in war in accordance with individuals’ liability. IHL's failure to consistently protect individual rights, specifically its shortfall compared to human rights law, has raised questions about IHL's adequacy also among international lawyers. This paper identifies the features of war that ground the inability of IL to regulate it to a level of moral acceptability and characterizes the quintessential war as presenting what I call an ‘epistemically cloaked forced choice’ regarding the preservation of individual rights. Commitment to the above moral standard, then, means that IL should not prejudge the outcome of wars and must, somewhat paradoxically, diverge from morality when making prescriptions about the conduct of hostilities. In showing that many confrontations between states inevitably take the form of such epistemically cloaked forced choices, the paper contests the argument by revisionist just-war theorists like McMahan that the failure of IL to track morality in war is merely a function of contingent institutional desiderata. IHL, with its moral limitations, has a continuing role to play in IR.



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1 In this paper I am concerned with international armed conflict.

2 Walzer, M., ‘Response to McMahan's Paper’, (2006) 34 Philosophia 43, at 43.

3 I use the terms IHL, laws of war, and laws of armed conflict interchangeably, despite their slightly different evocations.

4 The goal of avoiding systematic violations of individual rights in war makes it necessary to examine the legal regulation of not only deliberate attacks, but also the collateral damage or incidental harm inevitably inflicted in war. Given the limited space, this paper focuses only on the former and hence enquires into the ethical underpinnings and correct application of the principle of distinction, neglecting the principle of proportionality.

5 The most popular exposition of conventional JWT can be found in Walzer, M., Just and Unjust War: A Moral Argument with Historical Illustrations (2006); see more recently A. Margalit and M. Walzer, ‘Israel: Civilians and Combatants’, New York Review of Books, 14 May 2009, 21, at 22.

6 Walzer, supra note 5, at 144.

7 Ibid., at 145.

8 Combatants may be attacked even when they are too scared or incompetent to pose a threat or to effectively defend themselves. On the other hand, civilians, their threat potential/vulnerability notwithstanding, only lose their immunity through their actual conduct. The precise circumstances under which a civilian becomes a legitimate target due to direct participation in hostilities are subject to controversy. For comprehensive discussions of the issue, see Akande, D., ‘Clearing the Fog of War? The ICRC's Interpretive Guidance on Direct Participation in Hostilities’, (2010) 59 ICLQ 180; Melzer, N., Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law (2009).

9 This is the core of the revisionist critique of conventional JWT. It is mounted inter alia in Coady, C. A. J., ‘The Status of Combatants’, in Rodin, D. and Shue, H. (eds.), Just and Unjust Warriors: The Moral and Legal Status of Soldiers (2008), 153; Fabre, C., ‘Guns, Food, and Liability to Attack in War’, (2009) 120 Ethics 36; McMahan, J., ‘Laws of War’, in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 493; J. McMahan, Killing in War (2009); McMahan, J., ‘The Ethics of Killing in War’, (2004) 114 Ethics 693; D. Rodin, War Proportionality and Double Effect (forthcoming); D. Rodin, ‘The Moral Inequality of Soldiers: Why Jus in Bello Assymetry Is Half Right’, in Rodin and Shue, supra, 44.

10 McMahan, Killing in War, supra note 9, at 11.

11 Lazar identifies these three elements of liability as the common denominator among revisionist just-war theorists. Lazar, S., ‘The Morality and Law of War’, in Marmor, A. (ed.), Routledge Companion to Philosophy of Law (2012).

12 McMahan, J., ‘The Just Distribution of Harm between Combatants and Noncombatants’, (2010) 38 Philosophy & Public Affairs 343, at 354.

13 McMahan, Killing in War, supra note 9, at 234; also Rodin, ‘The Moral Inequality of Soldiers’, supra note 9, at 46.

14 ‘[U]nless they lose rights for some reason other than acquiring combatant status, just combatants are innocent in the relevant sense.’ McMahan, J., ‘The Moral Equality of Combatants’, (2006) 14 Journal of Political Philosophy 377, at 379; likewise Rodin, War Proportionality and Double Effect, supra note 9, at 167.

15 For an overview see D. Rodin and H. Shue, ‘Introduction’, in Rodin and Shue, supra note 9, 1, at 7.

16 The right to national self-defence under IL is far from congruent with JWT's concept of a just cause. However, in this section I only investigate the possibility of changing IHL without also challenging the prohibition of the use of force under general IL. I hence assume that self-defence in accordance with Article 51 UNC is the only just cause for resort to force and that individuals fighting on behalf of a belligerent state unable to avail itself of that justification are unjust combatants in the understanding of revisionist just-war theorists.

17 For an enquiry into the difficulties of determining the boundaries of the right to national self-defence under IL see Fletcher, G. P. and Ohlin, J. D., Defending Humanity: When Force is Justified and Why (2008), 63ff. For a comprehensive account of the equally heavy epistemic burden faced by combatants who are expected to determine the justness of their cause see S. Lazar, ‘The Responsibility Dilemma for Killing in War: A Review Essay’, (2010) Philosophy & Public Affairs 180.

18 Amongst others McMahan, ‘Laws of War’, supra note 9, at 358; McMahan (2009), supra note 9, at 42; see also McMahan, J., ‘The Prevention of Unjust Wars’, in Benbaji, Y. and Sussman, N. (eds.), Reading Walzer (2013).

19 A combatant can incur liability either by contributing to the unjustified threat her state poses to another or in a battlefield encounter by threatening another combatant who defends a just cause.

20 Lazar, S., ‘War’, in Lafollette, H. (ed.), International Encyclopaedia of Ethics (2011); for a similar argument see Dill, J. and Shue, H., ‘Limiting the Killing in War: Military Necessity and the St Petersburg Assumption’, (2012) 26 (3)Ethics and International Affairs 311.

21 Lazar, supra note 17, at 210.

22 Ibid., at 188.

24 Lazar, S., ‘Responsibility, Risk, and Killing in Self-Defense’, (2009) 119 Ethics 699, at 706.

25 For an enquiry into potential excuses of unjust combatants see J. Lichtenberg, ‘How to Judge Soldiers Whose Cause Is Unjust’, in Rodin and Shue, supra note 9, 112, at 118.

26 While most ethicists would consider mere agent-responsibility insufficient to ground liability to lethal harm, some revisionists have lowered their standards from requiring culpability to mere agent-responsibility. See for instance McMahan, J., ‘Duty, Obedience, Desert, and Proportionality in War: A Response’, (2011) 122 Ethics 1, at 19. For a discussion of this trend among revisionist just-war theorists see Lazar, supra note 24, at 706–2.

27 For an elaboration of the argument that the collective nature of war plays a crucial role in undermining the viability of revisionist JWT see Dill and Shue, supra note 20, passim.

28 For an exposition of this view see H. Shue, ‘Do We Need “a Morality of War”?’, in Rodin and Shue, supra note 9, 87.

29 Rodin has argued forcefully that the rights violations inflicted in war present so-called mala in se and should, therefore, never be levelled out with consequentialist reasoning. Rodin, D., ‘Morality and Law in War’, in Strachan, H. and Scheipers, S. (eds.), The Changing Character of War (2011) 455, at 460.

30 T. Nagel, Mortal Questions (1979), 84.

31 Nardin, T., ‘International Ethics’, in Reus-Smit, C. and Snidal, D. (eds.), Oxford Handbook of International Relations (2008), 594.

33 McMahan, Killing in War, supra note 9, at 3.

34 Out of the factors which commonly decide who wins a war – technological superiority, more people or better strategies in hurting the enemy – none is connected to the preservation of individual rights.

35 Sorell, T., ‘Morality and Emergency’, (2003) 103 Proceedings of the Aristotelian Society 21, at 22.

36 Ibid., at 23.

37 Foot, P., ‘Moral Realism and Moral Dilemma’, (1983) 80 Journal of Philosophy 7, at 379: P. Foot, Moral Dilemmas and Other Topics in Moral Philosophy (2002).

38 If we attach great enough moral significance to the difference between actions and omissions, we should not do anything at all to avert the imminent major loss in a forced-choice emergency with an epistemic cloak. I am inclined to think that, when the preservation of individuals’ right to life is concerned, the difference between actions and omissions alone should not be allowed to tip the scales against action.

39 It is beyond the scope of this paper to discuss the implications of numbers, meaning how many individuals’ rights have to be protected in order to warrant the overriding of some other individuals’ rights in the course of the use of force. Neither will I address whether it matters if we know who the respective individuals – beneficiaries and victims of the use of force – would be, whether their relationship to each other has any bearing on the justifiability of this reshuffling of harm or what likelihood of success the endeavour has to have. Scholars who juggle these parameters include A. Coates, ‘Is the Independent Application of Jus in Bello the Way to Limit War?’, in Rodin and Shue, supra note 9, 176; Fabre, supra note 9; Lazar, supra note 17; Rodin, War Proportionality and Double Effect, supra note 9.

40 Strictly speaking, in IHL as in most IL the international community speaks to states. In fact, wars are fought by individuals and that is who IHL's rules regarding the conduct of hostilities ultimately address.

41 J. Habermas, Between Facts and Norms: Contributions to a Discourse Theory (1996), 115.

42 For a conclusive argument that the logic of mere distinction is all IL can offer for the regulation of war, a more comprehensive enquiry into imaginable alternatives, which unfortunately is beyond the scope of this paper, would be desirable.

43 ‘Uncertainty is not a contingent feature of war; it is endemic, and radical. Perhaps [it is] sufficiently radical to discredit any attempt to transfer principles that govern extramilitary interpersonal conflicts from the sphere of ordinary life to that of war.’ Lazar, supra note 17, at 211.

44 Shue, supra note 28, at 96; also Lazar, supra note 24, at 699; likewise Waldron, who grants that it is tempting to judge law by a pure external standard of morality, but then insists that ultimately morality likewise has to be ‘viable’. Waldron, J., ‘Are Sovereigns Entitled to the Benefit of the International Rule of Law?’, (2011) 22 EJIL 315, at 3 and 8.

45 Shue, supra note 28, at 88. There is widespread agreement on this point; see McMahan, ‘Laws of War’, supra note 9, at 505; Shue, H., ‘Laws of War’, in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 511.

46 However, legal standards for evaluating action most certainly change depending on whether we are in war or in peace.

47 Similar J. McMahan, ‘The Morality of War and the Law of War’, in Rodin and Shue, supra note 9, 19, at 35. As related above, in the formation of public moral principles the consequences of their (correct) systematic implementation carry more weight than individuals' actions’ consequences do in the formation of moral principles addressed to the individual. But, once established, moral principles on neither level yield in the face of involuntary misapplication or impossibility of implementation.

48 J. Waldron, Vagueness and the Guidance of Action, (2010) New York University Public Law and Legal Theory Working Papers 10-81, at 16.

49 Cohen, J. L., ‘Sovereignty in the Context of Globalization: A Constitutionalist Pluralist Perspective’, in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 261.

50 Danilenko, G., Law-Making in the International Community (1993), 357.

51 Dupuy, R.-J., La communauté internationale entre mythe et l'histoire (1986); also Allott, P., Eunomia: New World Order for a New World (1990), 32, at 244; Simma, B., ‘From Bilateralism to Community Interest in International Law’, (1994) 250 Collected Courses of The Hague Academy of International Law, 217 at 247; Tomuschat, C., ‘Obligations Arising for States without or against Their Will’, (1993) 241 Collected Courses of The Hague Academy of International Law 195, at 227.

52 T. Meron, The Humanization of International Law (2006), 6–3.

53 Slaughter, A.-M. and Burke-White, W., ‘An International Constitutional Moment’, (2002) 43 Harv. ILJ 1.

54 Tomuschat, C., ‘Human Rights and International Humanitarian Law’, (2010) 21 EJIL 15, at 17.

55 Tomuschat interestingly makes the point that at least the ICCPR was likely drafted based on the conviction that it would cease to apply in war. Ibid., at 21.

56 Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 8 July 1996, [1996] ICJ Rep. 5, at 240, para. 25; see also Forowicz, M., The Reception of International Law in the European Court of Human Rights (2010), 314.

58 Amongst others Markovic and Others v. Italy, Judgment, 14 December 2006, Reports 2006, at para 100; Isayeva and Others v. Russia, Judgment, 24 February 2005, Reports 2005; Özkan v. Turkey, Judgment, 6 April 2004; Ergi v. Turkey, Judgment, 28 July 1998, Reports 1998-IV, at para 77; Güleç v. Turkey, Judgment, 27 July 1998, Reports 1998-IV, at paras. 63–64.

59 Forowicz, supra note 56, at 314.

60 Meron, T., ‘Extraterritoriality of Human Rights Treaties’, (1995) 89 AJIL 1, at 57; also Gross, A. M., ‘Human Proportions: Are Human Rights the Emperor's New Clothes of the International Law of Occupation?’, (2007) 18 EJIL 1; Hampson, F. J., ‘Using the International Human Rights Machinery to Enforce the International Law of Armed Conflict’, (1992) 31 Revue de droit militaire et de droit de la guerre 119.

61 Loizidou v. Turkey, Judgment, 18 December 1996, Reports 1996-VI, at para. 62.

62 The court denied jurisdiction in the latter case, on the grounds that the use of air power does not amount to effective control by the attacker, suggesting that air warfare maybe the last bastion against the encroachment of the use of force by HRL. Banković and Others v. Belgium and 16 Other Contracting States, Decision of Admissibility, 12 December 2001, Reports 2001-XII, at para 333.

63 Georgia v. Russia, Decision of Admissibility, 19 December 2011, not yet reported.

64 Tomuschat, supra note 54, at 23.

65 Forowicz, supra note 56, at 320; Watkin, K., ‘Controlling the Use of Force: A Role for Human Rights Norms in Contemporary Armed Conflict’, (2004) 98 AJIL 1, at 34.

66 For instance Martin, F. F., ‘The Unified Use of Force Rule Revisited: The Penetration of the Law of Armed Conflict by Human Rights Law, (2002) 65 Saskatchewan Law Review 406, at 408.

67 Melzer, supra note 8, at 77–82.

68 M. N. Schmitt, ‘The Interpretive Guidance on the Notion of Direct Participation in Hostilities: A Critical Analysis’, (2010) Harvard National Security Journal 5, at 14 and 40; also A. Cohen and Y. Shany, A Development of Modest Proportions: The Application of the Principle of Proportionality in the Israeli Supreme Court Judgement on the Lawfulness of Targeted Killings, International Law Forum, The Hebrew University of Jerusalem, Research Paper No. 5-07 (2007), at 8 ff. Green, L. C., ‘The “Unified Use of Force Rule” and the Law of Armed Conflict: A Reply to Professor Martin, (2002) 65 Saskatchewan Law Review 427, at 444.

69 This is specifically true for revisionist just-war theorists whose attempts to make law for the conduct of war track a morality based on individual rights are at a proper impasse.

* Janina Dill is the Hedley Bull Fellow at the Department of Politics and International Relations at the University of Oxford and a Research Fellow at Merton College []. I am grateful to Cecile Fabre, Seth Lazar, Jeff McMahan, David Rodin, Henry Shue, and Benjamin Valentino for their helpful comments as well as to the participants of the Annual Workshop of the Oxford Institute for Ethics, Law and Armed Conflict 2011, and the anonymous reviewers for this journal. All remaining errors are entirely my own responsibility.


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Should International Law Ensure the Moral Acceptability of War?



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