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Reflections on Proportionality, Military Necessity and the Clausewitzian War

  • Rotem M Giladi (a1)


This article explores the significance of the reference, in proportionality analyses, to proper purpose and legitimate ends, given the traditional aversion of international humanitarian law (IHL) to questions of (political) legitimacy. It demonstrates the centrality of that aversion in doctrinal assertions concerning the goals, characteristics and operational strategy of IHL yet argues that, at its historical and conceptual foundations, the law draws on a construction of war that presupposes legitimacy of the political type. That construction remains embedded, though implicit, in contemporary proportionality analyses.

Thus, the instrumental understanding of war by Carl von Clausewitz poses several challenges to entrenched contemporary doctrinal claims about the law, how it operates and the effects it produces. This provides an impetus for critical reassessment of the aversion to politics and the interaction between the humanitarian, military and political spheres in the operation of IHL norms. Such critique helps to identify novel strategies of humanitarian protection in war outside the confines demarcated by orthodox doctrine.



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1 See Schwarze, Jürgen, European Administrative Law (1st rev edn, Sweet & Maxwell 2006); Hartley, Trevor C, The Foundations of European Community Law (6th edn, Oxford University Press 2007); Koch, Oliver, Der Grundsatz der Verhältnismaßigkeit in der Rechtsprechung des Gerichtshofs der Europäische Gemeinschaften (Duncker & Humblot 2003); Nolte, Georg, ‘General Principles of German and European Administrative Law: A Comparison in Historical Perspective’ (1994) 57 Modern Law Review 191.

2 Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts (Protocol I) (entered into force 7 December 1978) 1125 UNTS 3 (‘Additional Protocol I’ or ‘AP I’), art 51(5)(b) (emphasis added). See also art 57(2)(a)(iii)–(b).

3 ibid.

4 ibid art 35(2) (‘superfluous injury or unnecessary suffering’), art 35(3) (‘widespread, long-term and severe damage to the natural environment’).

5 Geneva Convention (IV) Relative to the Protection of Civilian Persons in Time of War (entered into force 21 October 1950) 75 UNTS 287 (‘GC IV’), arts 41–43, 78.

6 ibid arts 55, 57.

7 See Sassòli, Marco, Bouvier, Antoine A and Quintin, Anne, How Does Law Protect in War? Cases, Documents and Teaching Materials on Contemporary Practice in International Humanitarian Law (3rd edn, Cambridge University Press 2011) 158; the authors treat proportionality as a ‘fundamental principle’ of IHL. See also Gardam, Judith G, Necessity, Proportionality and the Use of Force by States (Cambridge University Press 2004).

8 Sassòli, Marco, Article 43 of the Hague Regulations and Peace Operations in the Twenty-First Century (Humanitarian Policy and Conflict Research 2004) 10 (‘it is precarious to make the (end of) application of IHL dependent on criteria of legitimacy, as this blurs the distinction between jus ad bellum and jus in bello’).

9 AP I, Preamble. For the jus ad bellum/jus in bello distinction, its origin, validity, expression, and meaning see Giladi, Rotem, ‘The Jus Ad Bellum/Jus In Bello Distinction and the Law of Occupation’ (2008) 41 Israel Law Review 246.

10 Giladi, ibid 259.

11 Declaration Renouncing the Use, in Time of War, of Explosive Projectiles Under 400 Grammes Weight, St Petersburg (entered into force 11 December 1868) 1 American Journal of International Law Supp 95 (‘St Petersburg Declaration’), Preamble.

12 Charter of the United Nations and the Statute of the International Court of Justice (entered into force 24 October 1945) 1UNTS xvi.

13 Sassòli, Bouvier and Quintin, (n 7) 114. For discussion, see Lauterpacht, Hersch, ‘The Limits of the Operation of the Law of War’ (1953) 30 British Year Book of International Law 206; Meron, Theodor, ‘The Humanization of Humanitarian Law’ (2000) 94 American Journal of International Law 239, 241.

14 This appeal was made at the 1863 Geneva Conference by Gustave Moynier, speaking for the Committee to become the International Committee of the Red Cross (ICRC): quoted in Durand, André, ‘Gustave Moynier and the Peace Societies’ (1996) 314 International Review of the Red Cross 532, 532–33. On the ICRC's equivocal stand on pacifism, see Moorehead, Caroline, Dunant's Dream: War, Switzerland and the History of the Red Cross (Carroll & Graf 1999) 164–71. See also Best, Geoffrey, Humanity in Warfare: The Modern History of the International Law of Armed Conflicts (Weidenfeld and Nicolson 1980) 910.

15 See, for example, AP I, art 4.

16 Viotti, Aurélio, ‘In Search of Symbiosis: the Security Council in the Humanitarian Domain’ (2007) 89 International Review of the Red Cross 131, 132. See also Giladi (n 9) 256–57.

17 Greenwood, Christopher, ‘The Relationship Between Ius ad Bellum and Ius in Bello’ (1983) 9 Review of International Studies 221, 226; Lauterpacht (n 13) 212; Dinstein, Yoram, War, Aggression and Self-Defence (2nd edn, Cambridge University Press 1994). See also Walzer, Michael, Just and Unjust Wars: A Moral Argument with Historical Illustrations (4th edn, Basic Books 2006) 41, 4445.

18 Pictet, Jean, Humanitarian Law and the Protection of War Victims (Sijthoff 1975) 19.

19 Sassòli, Bouvier, and Quintin (n 7) 115 (‘This complete separation between jus ad bellum and jus in bello … also implies, however, that the rules of IHL are not to be drafted so as to render jus ad bellum impossible to implement, e.g., render efficient self-defence impossible’).

20 ibid 93–94, especially notes 15–16.

21 ICRC, ‘General Problems in Implementing the Fourth Geneva Convention’, Report to the Meeting of Experts, Geneva, 27–29 October 1998, available at

22 ibid.

23 Thus, ‘One of the strongest arguments used to convince belligerents to respect IHL is that they can achieve victory while respecting IHL and that IHL will even make victory easier, because it ensures that they concentrate on what is decisive, the military potential of the enemy’: Sassòli, Bouvier and Quintin (n 7) 439.

24 Lamp, Nicolas, ‘Conceptions of War and Paradigms of Compliance: The “New War” Challenge to International Humanitarian Law’ (2011) 16 Journal of Conflict & Security Law 225, 231 (‘In order to accommodate what is assumed to be this single immediate aim in warfare, IHL accepts, via the doctrine of military necessity, that the warring parties need to be able to attain military victory by attacking combatants and military objectives of the enemy’). For a contrary view, see, for example, Blum, Gabriella, ‘The Laws of War and the Lesser Evil’ (2010) 35 Yale Journal of International Law 1.

25 But see the ICRC Commentary on AP I art 35: Pilloud, Claude and others (eds), Commentary on the Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949 (International Committee of the Red Cross, Martinus Nijhoff 1987) 393 (‘Military necessity means the necessity for measures which are essential to attain the goals of war, and which are lawful in accordance with the laws and customs of war’).

26 St Petersburg Declaration (n 11).

27 Of the nineteenth century early instruments of the modern laws of war, the St Petersburg Declaration seems among those that draw the least academic attention; even Gasser dedicates no more than four pages to this instrument: Gasser, Hans-Peter, ‘A Look at the Declaration of St Petersburg of 1868’ (1993) 33 International Review of the Red Cross 511. The dearth of writing – and its narrow focus – is further demonstrated by Meyrowitz, Henri, ‘The Principle of Superfluous Injury or Unnecessary Suffering: From the Declaration of St Petersburg of 1868 to Additional Protocol I of 1977’ (1994) 34 International Review of the Red Cross 98; Best (n 14) 160; and Neff, Stephen C, War and the Law of Nations: A General History (Cambridge University Press 2005).

28 Gasser, ibid 511.

29 ibid 513.

30 Best, Geoffrey, War & Law Since 1945 (Oxford University Press 1994) 4243.

31 Covenant of the League of Nations (entered into force 28 April 1919), 11 Martens Nouveau Receuil (ser 3) 331.

32 Treaty providing for the Renunciation of War as an Instrument of National Policy (entered into force 24 July 1929) available at

33 Carl Philipp Gottfried von Clausewitz (1780–1831), Prussian soldier and military theorist, author of the posthumously published influential military theory work Vom Kriege: von Clausewitz, Carl, On War (1832, Howard, Michael and Paret, Peter (eds and trs), Princeton University Press 1984) (‘On War’). On Clausewitz and his place in modern military thought, see Paret, Peter, Clausewitz and the State: The Man, His Theories, and His Times (Princeton University Press 2007); ‘Clausewitz’ in Paret, Peter (ed), Makers of Modern Strategy from Machiavelli to the Nuclear Age (Princeton University Press 1986) 186.

34 This dialectical distinction between ‘the pure concept of war and the concrete form that, as a general rule, war assumes’ (Clausewitz, ibid 579) pervades Clausewitz's war theory, but see especially ibid 580: ‘We must … be prepared to develop our concept of war as it is ought to be fought, not on the basis of its pure definition, but by leaving room for every sort of extraneous matter. We must allow for natural inertia, for all the friction of its parts, for all the inconsistency, imprecision, and timidity of man; and finally we must face the fact that war and its forms result from ideas, emotions, and conditions prevailing at the time.’

35 ibid 99: ‘Strictly speaking war is neither an art nor a science. … war … is part of man's social existence. War is a clash between major interests, which is resolved by bloodshed – that is the only way in which it differs from other conflicts. Rather than comparing it to art we could more accurately compare it to commerce, which is also a conflict of human interests and activities, and it is still closer to politics, which in turn may be considered as a kind of commerce on a larger scale. Politics, moreover, is the womb in which war develops’ (emphasis in the original).

36 ibid, 266, 526. Compare to Sassòli, Bouvier and Quintin (n 7) 93 note 15 (‘The state fighting in self-defense has only to weaken the military potential of the aggressor sufficiently to preserve its independence; the aggressor has only to weaken the military potential of the defender sufficiently to impose its political will; the governmental forces involved in a non-international armed conflict have only to overcome the armed rebellion and dissident fighters have only to overcome the control of the government of the country (or parts of it) they want to control’).

37 Clausewitz, ibid 75; Heuser, Beatrice, ‘Clausewitz's Ideas of Strategy and Victory’ in Strachan, Hew and Herberg-Rothe, Andreas (eds), Clausewitz in the Twenty-First Century (Oxford University Press 2007) 138, 144. See also Martel, William C, Victory in War: Foundations of Modern Military Policy (Cambridge University Press 2007).

38 Clausewitz, ibid 90–91.

39 ibid 87; ibid 75, on the law of war: ‘War is thus an act of force to compel an enemy to do our will …; to impose our will on the enemy is its object’ (emphasis in the original). See Daniel Moran, ‘The Instrument: Clausewitz on Aims and Objectives in War’, in Strachan and Herberg-Rothe (n 37) 91.

40 In the Clausewitzian war, writes Peter Paret, ‘[t]he political purpose for which a war is fought should determine the means that are employed and the kind and degree of effort required. The political purpose should also determine the military objective’: Paret, ‘Clausewitz’ (n 33) 206–07; see Clausewitz, ibid 80–81. While the military purpose ‘is dependent on the political purpose’, it also depends on other factors: ibid 585–86. On the escalatory tendency of war, see, for example, ibid 589.

41 Clausewitz, ibid 585.

42 Paret, ‘Clausewitz’ (n 33) 207.

43 Clausewitz (n 33) 585–89; see also 77–78.

44 ibid 585–89.

45 ibid 585.

46 Paret, ‘Clausewitz’ (n 33) 199, 213.

47 Clausewitz (n 33) 75 (emphases in the original). For conflicting evaluations of Clausewitz's position on law in war see, eg, Green, LC, ‘Cicero and Clausewitz or Quincy Wright: The Interplay of Law and War’ (1998) 9 United States Airforce Academy Journal of Legal Studies 59; cf van Creveld, Martin, ‘The Clausewitzian Universe and the Law of War’ (1991) 26 Journal of Contemporary History 403.

48 US War Department, Instructions for the Government of Armies of the United States in the Field, General Orders No. 100, 24 April 1863 (emphasis added). I explore the central role that the instrumentality of war plays in its restraint in the Lieber Code in Giladi, Rotem, ‘A Different Sense of Humanity: Occupation in Francis Lieber's Code’ (2012) International Review of the Red Cross (forthcoming). Though acknowledged as the first modern codification of the laws of war, and as a highly influential precedent of what was to follow, the Lieber Code and, in particular, the roots of the concept of humanity it enacts still await systematic uncovering. Otherwise, see Baxter, Richard R, ‘The First Modern Codification of the Law of War: Francis Lieber and General Orders No. 100’ (1963) 25 International Review of the Red Cross 171, 183; Carnahan, Burrus M, ‘Lincoln, Lieber and the Laws of War: The Origins and Limits of the Principle of Military Necessity’ (1998) 92 American Journal of International Law 213.

49 Creveld, Martin van, The Transformation of War (The Free Press 1991).

50 Gat, Azar, War in Human Civilization (Oxford University Press 2006).

51 Clausewitz (n 33) 87.

52 US Department of the Army, Joint Publication 3-0: Joint Operations, February 2008, §1–68 (emphasis in the original).

53 ‘Termination design is driven in part by the nature of the conflict itself … The underlying causes of a particular conflict – cultural, religious, territorial, resources, or hegemonic – should influence the understanding of conditions necessary for joint operation termination and conflict resolution’; ibid §IV–7.

54 Declaration on the Inadmissibility of Intervention and Interference in the Internal Affairs of States, UNGA Res 36/103, UN Doc A/Res/36/103 (1981), 9 December 1981, Preamble.

55 Legitimisation obviates the need to inquire, in concrete cases, into the propriety of purpose: the legitimate purpose is the conduct of war per se. As long as a measure can be couched in terms of military necessity, and is not strictly unlawful ‘in accordance with the laws and customs of war’, the legitimacy of the end for which it is employed would remain presumed. Thus, IHL permits what may well amount to indefinite detention of civilians in occupied territories if the occupant considers it ‘necessary, for imperative reasons of security’. GC IV (n 5), art 78, presupposes, in other words, that the occupant may legitimately enforce its control over the territory it occupies, and that it occupies the territory for legitimate reasons. Military necessity is predominantly permissive, not restrictive. Charter norms make this presupposition unwarranted. IHL refrains from engaging questions of purpose; in doing so, in effect, it validates all purposes as proper.

56 Text accompanying n 14.

57 Discussed by Best (n 14) 14; but cf 120.

58 Text following n 40.

59 Pictet (n 18) 15.

60 Text following nn 30, 50.

61 I seek some answers to this question in Rotem Giladi, ‘Rites of Affirmation: Progress and Immanence in International Humanitarian Law Historiography’ (on file with the author).

62 GC IV (n 5), art 55.

63 Text to n 2.

64 Sassòli, Bouvier and Quintin (n 7) 114. See also Giladi (n 9).

65 Greenwood (n 17) 226; Giladi, ibid 257–58.

66 Giladi, ibid 258–59; Sassòli, Bouvier and Quintin (n 7) 114–15; Greenwood, ibid 226.

67 Greenwood, Christopher, ‘Historical Development and Legal Basis’ in Fleck, Dieter (ed), The Handbook of Humanitarian Law in Armed Conflicts (2nd edn, Oxford University Press 2009) 1, 11. See also sources cited (n 17); Giladi, ibid 259.

68 Sassòli, Bouvier and Quintin (n 7) 115 (‘from the humanitarian point of view, the victims of the conflict on both sides need and deserve the same protection’).

69 Greenwood (n 17) 227 (the purpose of humanitarian norms, rather than to confer benefits onto parties to a conflict, is ‘to protect individuals and to give expression to concepts of international public policy’).

70 Giladi (n 9) 259–60.

71 Akin to the line of thought proposed by Mcmahan, Jeff, Killing in War (Oxford University Press 2009).

72 Matheson, Michael J, Council Unbound: The Growth of UN Decision Making on Conflict and Postconflict Issues after the Cold War (United States Institute of Peace Press 2006).

73 Hague Convention (II) with Respect to the Laws and Customs of War on Land and its annex: Regulations concerning the Laws and Customs of War on Land (entered into force 4 September 1900) 187 CTS 429, Preamble. On lawyers as the authoritative speakers of public conscience, see Koskenniemi, Martti, The Gentle Civilizer of Nations: The Rise and Fall of International Law 1870–1960 (Cambridge University Press 2004) 41 and Giladi (n 61).

74 cf Blank, Laurie R, ‘A New Twist on an Old Story: Lawfare and the Mixing of Proportionalities’ (2011) 43 Case Western Reserve Journal of International Law 707.

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