1 The term ‘principle of equal application’ and variants thereto is used here because it is consistent with the intent of the ‘scope of application’ provisions of the Geneva Conventions and other treaties on the laws of war. In Rodin and Shue, above note *, some contributors use the phrase ‘symmetry thesis’ to refer to this principle. I have not followed this usage because what is at stake is an established legal principle, not a mere thesis or proposition; and the principle does not depend on an assumption that there is symmetry between belligerents.

2 For a useful discussion, including extensive references to sources, see Marco Sassòli, ‘Ius ad bellum and ius in bello – the separation between the legality of the use of force and humanitarian rules to be respected in warfare: crucial or outdated?’, in Michael N. Schmitt and Jelena Pejic (eds.), International Law and Armed Conflict: Exploring the Faultlines – Essays in Honour of Yoram Dinstein, Martinus Nijhoff, Leiden, 2007, pp. 241–64.

3 Adam Roberts, ‘Humanitarian issues and agencies as triggers for international military action’, International Review of the Red Cross, No. 839 (2000), pp. 673–98.

4 Greenwood, Christopher, ‘The relationship between ius ad bellum and ius in bello’, Review of International Studies, Vol. 9 (4) (1983), pp. 221–34CrossRefGoogle Scholar. See also ‘The applicability of international humanitarian law and the law of neutrality to the Kosovo campaign’, Israel Yearbook on Human Rights, Vol. 31 (2001), pp. 111–44, esp. at p. 143, where he emphasizes that a jus ad bellum requirement that the use of force should be proportionate ‘should never be used to undermine the principle of the equal application of the jus in bello’.

5 See, e.g., the International Court of Justice's reference to ‘an extreme circumstance of self-defence’ in the advisory opinion on The Legality of the Threat or Use of Nuclear Weapons, 1996, para. 105(2) E. Self-defence is discussed further below in the section on certain arguments for varying the law in favour of particular parties, text at note 42.

6 The effects of UN authorization on the principle of equal application are discussed further below in the section on certain arguments for varying the law in favour of particular parties, text at note 53.

7 For explorations by two philosophers of the proposition that jus in bello should be applied in an unequal manner, e.g., to help protect soldiers who are fighting in a cause which has been authoritatively accepted as just under jus ad bellum, see the chapters by Jeff McMahan and David Rodin in Rodin and Shue (eds.), above note *, pp. 19–43, 44–68.

8 Amendment Article 1 of the 1980 Convention on Certain Conventional Weapons, 21 December 2001. There are 63 states parties to this amendment. Information from www.icrc.org/ihl (last visited 1 October 2008).

9 See, e.g., the following UN Security Council resolutions reaffirming (in armed conflicts that were to a significant degree non-international in character) that all parties are bound to comply with their ‘obligations under international humanitarian law and in particular the Geneva Conventions of 12 August 1949’: SC Res. 764 of 13 July 1992 on Bosnia and Herzegovina, and SC Res. 1193 of 28 August 1998 on Afghanistan.

10 SC Res. 1624 of 14 September 2005, passed at a ‘summit’ meeting of the UN Security Council attended by heads of state and government.

11 In its judgment on 29 June 2006 in the case of Hamdan v. Rumsfeld, which concerned the status and treatment of detainees suspected of involvement in terrorism, the US Supreme Court placed emphasis on both Common Article 3 of the 1949 Geneva Conventions, and Article 75 of 1977 Additional Protocol I. This confirmed a more general tendency to view the provisions of Common Article 3 as applicable in a wider range of circumstances than simply civil war within a state (which is what a strict reading of that article's ‘scope of application’ wording might suggest).

12 The application of the laws of war in the war in Bosnia and Herzegovina in 1992–5 is discussed further below under the headings ‘UN-authorized forces in enforcement actions’ and ‘UN peacekeeping forces’.

13 All laws-of-war treaties mentioned in this survey may be found at www.icrc.org/ihl (last visited 3 September 2008). Agreements concluded up to 1999 are in Adam Roberts and Richard Guelff (eds.), Documents on the Laws of War, 3rd edn, Oxford University Press, Oxford, 2000.

14 For an authoritative account of the origins and meanings of Common Article 1 of the 1949 Geneva Conventions, see Kalshoven, Frits, ‘The undertaking to respect and ensure respect in all circumstances: from tiny seed to ripening fruit’, Yearbook of International Humanitarian Law, Vol. 2 (1999), T. M. C. Asser Press, The Hague, 2000, pp. 3–61.CrossRefGoogle Scholar

15 1949 Geneva Conventions, Common Article 2.

16 1977 Protocol I, preamble.

17 Ibid., Article 1(1) and (4).

18 Ibid., Article 96(3).

19 On the ambiguities of the Grotian tradition of thought about limitations in war and their relation to jus ad bellum issues, see Hedley Bull, Benedict Kingsbury and Adam Roberts (eds.), Hugo Grotius and International Relations, Clarendon Press, Oxford, 1990, pp. 15–26 (Kingsbury and Roberts), and pp. 194–207 (Draper).

20 Emmerich de Vattel, Le droit des gens (posthumous edition, 1773 [1758]). The edition cited here is The Law of Nations; or, Principles of the Law of Nature, applied to the Conduct and Affairs of Nations and Sovereigns, ed. Joseph Chitty, Sweet, Stevens and Maxwell, London, 1834, pp. 382–3. The citation is from book III, ch. 12, §§ 190–1.

21 Ibid. §§ 191–2.

22 Jean-Jacques Rousseau, Du Contrat Social, ou Principes du Droit Politique (1762), paragraph I.iv, in Rousseau: The Social Contract and other Later Political Writings, ed. and trans. Victor Gourevitch, Cambridge University Press, Cambridge, 1997, pp. 46–7.

23 See, e.g., François Bugnion, The International Committee of the Red Cross and the Protection of War Victims, Macmillan Education, Oxford, 2003, pp. 125, 717.

24 1856 Paris Declaration on Maritime Law, preamble.

25 Official lists show that as at May 1949 there were 59 member states of the UN. Information from www.un.org/members (last visited 1 October 2008).

26 Information on states party to the 1949 Geneva Conventions from www.icrc.org/ihl (last visited 1 October 2008).

27 On the IMT at Nuremberg, see section on reciprocity below, text at note 36.

28 Trials of War Criminals before the Nuernberg Military Tribunals under Control Council Law No. 10, Nuernberg, October 1946–April 1949, 15 vols., Government Printing Office, Washington DC, 1949–53, XI, p. 1247.

29 See, e.g., the clear enunciation of ‘universal application of the law of armed conflict’ in The Manual of the Law of Armed Conflict, UK Ministry of Defence, Oxford University Press, Oxford, 2004, p. 34; and the excellent discussion of ‘equal application of the jus in bello’ by Yoram Dinstein in his War, Aggression and Self-Defence, 4th edn, Cambridge University Press, Cambridge, 2005, pp. 156–63.

30 Resolution I, ‘Respect for international humanitarian law in armed conflicts and action by the ICRC for persons protected by the Geneva Conventions’, Handbook of the International Red Cross and Red Crescent Movement, 13th edn, ICRC and IFRC, Geneva, 1994, p. 752.

31 Rule 139, in Jean-Marie Henckaerts and Louise Doswald-Beck (eds.), Customary International Humanitarian Law, 2 vols., ICRC and Cambridge University Press, Cambridge, 2005, I (Rules), p. 495.

32 For a useful listing of such UN resolutions see Ibid., II (Practice), pp. 3168–72.

33 Pejic, Jelena, ‘Non-discrimination and armed conflict’, International Review of the Red Cross, No. 841 (2001), pp. 183–94.Google Scholar

34 1949 Geneva Conventions, Common Article 2, the terms of which are reflected in ‘scope of application’ provisions of a number of subsequent treaties on the laws of war.

35 Some of the states that had made such reservations to the 1925 Geneva Protocol subsequently withdrew them, because preserving any right of like-for-like retaliation against biological or chemical weapons was considered inconsistent with their obligations under the 1972 Biological Weapons Convention and the 1993 Chemical Weapons Convention prohibiting possession of such weapons.

36 The Trial of German Major War Criminals: Proceedings of the International Military Tribunal Sitting at Nuremberg Germany, HMSO, London, 23 vols., 1946–51, Part 22, p. 467.

37 1960 Vienna Convention on the Law of Treaties, Article 60(5).

38 Rule 140 in Henckaerts and Doswald-Beck, above note 31, I, pp. 498–9. In the account of this and the preceding rule there is no exploration of reciprocity in observance of the conventions.

39 Including the 1999 Second Hague Protocol for the Protection of Cultural Property in the Event of Armed Conflict, Article 3(2).

40 For a critical view of reprisals see Frits Kalshoven, Belligerent Reprisals, Sijthoff, Leyden, 1971.

41 The limitations on reprisals in 1977 Additional Protocol I are mainly in Articles 51–56. Certain states, when indicating adherence to the treaty, made reservations and declarations to these articles. That of the United Kingdom – statement ‘m’ in Roberts and Guelff, above note 13, p. 511 – is notably explicit on this point.

42 ‘Radio report to the American people on the Potsdam Conference’, 9 August 1945, Public Papers of the Presidents of the United States: Harry S. Truman, 1945, GPO, Washington DC, 1961, p. 212. This broadcast was on the day of the Nagasaki bombing.

43 Pfanner, Toni, ‘Asymmetrical warfare from the perspective of humanitarian law and humanitarian action’, International Review of the Red Cross, No. 857 (2005), pp. 149–74CrossRefGoogle Scholar. In the conclusion he states, ‘International humanitarian law should not be overstretched. It cannot be extended to situations other than those it was intended to cover without giving wrong directives’ (p. 173).

44 See especially Rogers, A. P. V., ‘Unequal combat and the law of war’, Yearbook of International Humanitarian Law, Vol. 7 (2004), pp. 3–34.CrossRefGoogle Scholar See especially the list of reasons why things go wrong, at pp. 33–4.

45 This issue is explored further in Adam Roberts, ‘Air power, accuracy, and the law of targeting: why no brave new world?’, in Richard B. Jaques (ed.), Issues in International Law and Military Operations, International Law Studies, Vol. 80, US Naval War College, Newport, Rhode Island, 2006, pp. 133–50.

46 Brig. Gen. Charles Dunlap, ‘Air and information operations: a perspective on the rise of “lawfare” in modern conflicts’, presentation prepared for the US Naval War College Conference on Current Issues in International Law and Military Operations, Newport RI, 25–27 June 2003. For a brief summary of his views on ‘lawfare’, see his chapter, ‘Legal issues in coalition warfare: a US perspective’, in Anthony M. Helm (ed.), The Law of War in the 21st Century: Weaponry and the Use of Force, International Law Studies, Vol. 82, US Naval War College, Newport, RI, 2006, at pp. 227–8.

47 See, e.g., the terms of the 1936 London Procès-Verbal on Submarine Warfare against Merchant Ships.

48 Information on states parties to these treaties from www.icrc.org/ihl (last visited 1 October 2008).

49 In September 2008 the US Senate gave favourable advice and consent to US ratification of the following five agreements: 1954 Hague Cultural Property Convention, 2001 CCW amended Article 1 (expanded scope of application), 1980 CCW Protocol III (incendiary weapons), 1995 CCW Protocol IV (blinding laser weapons), and 2003 CCW Protocol V (explosive remnants of war). Information from www.senate.gov/pagelayout/legislative/one_item_and_teasers/trty_rtf.htm (last visited 1 October 2008). Acts of ratification with depositaries were expected to follow promptly.

50 Several US official publications indicated that the US viewed certain provisions of 1977 Protocol I as either legally binding as customary international law or acceptable practice although not legally binding. See, e.g., Operational Law Handbook 2003, US Army, International and Operational Law Department, Judge Advocate General's School, Charlottesville, VA, ch. 2, p. 11. Subsequent editions of this handbook have not contained this statement.

51 US attempts to secure immunity for its forces from investigation and prosecution by the ICC have included UN Security Council resolutions mentioned below in note 54; and the pursuit of bilateral immunity agreements (often called ‘Article 98 agreements’) with individual states.

52 See below discussion of the problem of the ‘innocent soldier’, pp. 28–31.

53 See, e.g., Gary Sharp, Walter, ‘Protecting the avatars of international peace and security’, Duke Journal of International and Comparative Law, Vol. 7 (1996), pp. 93–183.Google Scholar This article contained as an appendix (pp. 175–83) a draft additional protocol to the 1949 Geneva Conventions which would have provided that personnel in any operation authorized or mandated by the competent organ of the UN may in no circumstances be attacked.

54 SC Res. 1422 of 12 July 2002. Renewed by SC Res. 1487 of 12 June 2003. Not renewed in 2004 owing to the controversy over the Abu Ghraib scandal. Not renewed subsequently.

55 For a useful exploration see Christopher Greenwood, ‘International humanitarian law and united nations military operations’, Yearbook of International Humanitarian Law, Vol. 1 (1998), pp. 3–34.

56 See, e.g., SC Res. 757 of 30 May 1992, imposing economic sanctions on the Federal Republic of Yugoslavia (Serbia and Montenegro), para. 11.

57 SC Res. 1483 of 22 May 2003, preamble and para. 8. For a discussion see Marten Zwanenberg, ‘Existentialism in Iraq: Security Council Resolution 1483 and the law of occupation’, International Review of the Red Cross, No. 854 (2004), pp. 745–68.

58 SC Res. 781 of 9 October 1992, establishing the ban on military flights over Bosnia. The ban did not apply to UNPROFOR flights or to other flights in support of UN operations.

59 SC Res. 816 of 31 March 1993, extending the ban to encompass helicopters and authorizing members states to use ‘all necessary measures’ to enforce the ban.

60 SC Res. 819 of 16 April 1993, establishing Srebrenica as a ‘safe area’; SC Res. 824 of 6 May 1993, extending the concept of ‘safe areas’ to Sarajevo, Tuzla, Zepa, Gorazde and Bihac; and SC Res. 836 of 4 June 1993, providing for enforcement by UNPROFOR and by member states (i.e. NATO).

61 Statute of the International Criminal Tribunal for the former Yugoslavia, adopted by SC Res. 827 of 25 May 1993. In the drafting process there was no suggestion that violations of Security Council resolutions per se might form part of the subject matter of the Tribunal.

62 1994 UN Convention on the Safety of United Nations and Associated Personnel, Article 2(2). The provisions of this convention are reflected in the 1998 Rome Statute of the International Criminal Court, Article 8(2)(b)(iii) and (e)(iii).

63 Promulgated in UN Doc. ST/SGB/1999/13 of 6 August 1999. Reprinted in Roberts and Guelff, above note 13, pp. 725–30.

64 See detailed statistics in ‘UN peacekeeping fatalities by year and incident type’, available at www.un.org/Depts/dpko/fatalities (last visited 3 September 2008).

65 For a critical general survey of the UN Security Council's involvement in a range of matters relating to the laws of war see Viotti, Andréa, ‘In search of symbiosis: the Security Council in the humanitarian domain’, International Review of the Red Cross, No. 865 (2007), pp. 131–53.CrossRefGoogle Scholar

66 For findings of guilt, sentences and dissenting opinion at Nuremberg on 1 October 1946, see The Trial of German Major War Criminals: Proceedings of the IMT at Nuremberg, Part 22, pp. 485–547.

67 GA Res. 3314 (XXIX) of 14 December 1974, which includes ‘Annex: Definition of Aggression’.

68 1998 Rome Statute of the International Criminal Court, Articles 5(2), 121 and 123.

69 For a recent survey see Adam Roberts, ‘Human rights obligations of external military forces’, in The Rule of Law in Peace Operations: ‘Recueils’ of the International Society for Military Law and the Law of War, 17th International Congress, Scheveningen, 16–21 May 2006, ISMLLW, Brussels, 2006 (i.e. February 2007), pp. 429–49.

70 1864 Geneva Convention for the Amelioration of the Condition of the Wounded in Armies in the Field, Article 6.

71 1868 St Petersburg Declaration Renouncing the Use, in Time of War, of Explosive Projectiles under 400 Grammes Weight, preamble.

72 1980 UN Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons which May be Deemed to be Excessively Injurious or to Have Indiscriminate Effects, and its Protocols.

73 1998 Rome Statute of the International Criminal Court, Article 8(2)(b)(xx).

74 For the classic exposition see B. H. Liddell Hart, Strategy: The Indirect Approach, rev. edn, Faber, London, 1967.

75 For details see Roberts, Adam, ‘The laws of war in the 1990–91 Gulf conflict’, International Security, Vol. 18 (Winter 1993/94), pp. 170–2CrossRefGoogle Scholar. For a wide range of propaganda leaflets, including those used in the 1991 Gulf War to encourage Iraqis to walk away from their military vehicles, see the Aerial Propaganda Leaflet Database of the website of the PsyWar Society, available at www.psywar.org/leaflets.php (last visited 3 September 2008).

76 For a critical evaluation of the US strategy of bringing the effects of war home to enemy civilians, see Thomas, Ward, ‘Victory by duress: civilian infrastructure as a target in air campaigns’, Security Studies, Vol. 15 (January–March 2006), pp. 1–33.CrossRefGoogle Scholar