1 Geneva Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field of 12 August 1949, 75 UNTS 31 (entered into force 21 October 1950); Geneva Convention (II) for the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of Armed Forces at Sea of 12 August 1949, 75 UNTS 85 (entered into force 21 October 1950); Geneva Convention (III) relative to the Treatment of Prisoners of War of 12 August 1949, 75 UNTS 135 (entered into force 21 October 1950); Geneva Convention (IV) relative to the Protection of Civilian Persons in Time of War of 12 August 1949, 75 UNTS 287 (entered into force 21 October 1950).

2 Pejić, Jelena, “The Protective Scope of Common Article 3: More than Meets the Eye”, International Review of the Red Cross, Vol. 93, No. 881, 2011, pp. 197–198CrossRefGoogle Scholar; Lindsay Moir, The Law of Internal Armed Conflict, Cambridge University Press, Cambridge, 2002, pp. 52–88; Somer, Jonathan, “Jungle Justice: Passing Sentence on the Equality of Belligerents in Non-International Armed Conflict”, International Review of the Red Cross, Vol. 89, No. 867, 2007, p. 661CrossRefGoogle Scholar. See also La Rosa, Anne-Marie and Wuerzner, Carolin, “Armed Groups, Sanctions and the Implementation of International Humanitarian Law”, International Review of the Red Cross, Vol. 90, No. 870, 2008, p. 328CrossRefGoogle Scholar. Throughout this paper, the term “AG” will be used in a very general sense, including both armed groups fighting against each other and those fighting against governments. For a brief explanation on how these terms are being used in the international realm, see Ezequiel Heffes, Marcos D. Kotlik and Brian E. Frenkel, “Addressing Armed Opposition Groups through Security Council Resolutions: A New Paradigm?”, in Frauke Lachenmann, Tilman J. Röder and Rüdiger Wolfrum (eds.), Max Planck Yearbook of United Nations Law, Vol. 18, Brill Nijhoff, Leiden and Boston, MA, 2015, pp. 43–45.

3 Yves Sandoz, Christophe Swinarski and Bruno Zimmermann, Commentary on the Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949, ICRC, Geneva, 1987, p. 1372, fn. 18; L. Moir, above note 2, pp. 65–67; Liesbeth Zegveld, Accountability of Armed Opposition Groups in International Law, Cambridge University Press, Cambridge, 2002, p. 152; Marco Sassòli, “Possible Legal Mechanisms to Improve Compliance by Armed Groups with International Humanitarian Law and International Human Rights Law”, paper submitted at the Armed Groups Conference, 2003, p. 6.

4 See, e.g., International Criminal Tribunal for Rwanda (ICTR), The Prosecutor v. Jean-Paul Akayesu, Case No. ICTR-96-4-T, Judgment (Trial Chamber), 2 September 1998, paras 608–609; Special Court for Sierra Leone (SCSL), The Prosecutor v. Morris Kallon and Brima Bazzy Kamara, Case No. SCSL-04-15-PT-060, Decision on Challenge to Jurisdiction: Lomé Accord Amnesty, 13 March 2004, paras 45–47. See also J. Pejić, above note 2, pp. 197–198; L. Moir, above note 2, p. 56; J. Somer, above note 2, p. 661.

5 ICJ, Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Judgment, ICJ Reports 1986, para. 218.

6 L. Moir, above note 2, p. 88. Of course, it cannot be ignored that many shortcomings of the GCs were dealt with to some extent within the framework of the 1977 Additional Protocols (AP I and AP II) – specifically, AP II develops and supplements CA3 and addresses important matters such as the protection of the civilian population. Additionally, many rules of customary IHL have also developed as applicable to non-international armed conflicts. See Jean-Marie Henckaerts and Louise Doswald-Beck (eds), Customary International Humanitarian Law, Vol. 1: Rules, Cambridge University Press, Cambridge, 2005 (ICRC Customary Law Study), p. xxxiv.

7 Christopher Greenwood, “Scope of Application of Humanitarian Law”, in Dieter Fleck (ed.), The Handbook of Humanitarian Law in Armed Conflict, Oxford University Press, Oxford, 2008, p. 56. For an explanation on the existence of special agreements even before CA3, see Veuthey, Michel, “Learning from History: Accession to the Conventions, Special Agreements and Unilateral Declarations”, Collegium, No. 27, 2003, pp. 140–143Google Scholar.

8 Recent surveys have concluded that the great majority of ongoing armed conflicts around the world are non-international. According to different sources, the total number of armed conflicts in recent years fluctuates between thirty and thirty-eight, and only two or three of them are considered to be international. See Stuart Casey-Maslen (ed.), The War Report 2013, Oxford University Press, Oxford, 2014, pp. 28–29; Stuart Casey-Maslen (ed.), The War Report 2012, Oxford University Press, Oxford, 2013, pp. 3–4. See also data available from the Uppsala Conflict Data Program, available at: www.pcr.uu.se/research/ucdp/.

9 See Olivier Bangerter, “Internal Control: Codes of Conduct within Insurgent Armed Groups”, in Small Arms Survey, Occasional Paper No. 31, November 2012, pp. 4 ff., available at: www.smallarmssurvey.org/fileadmin/docs/B-Occasional-papers/SAS-OP31-internal-control.pdf; Marcos Kotlik, “Reconocimiento de beligerancia y uso de la fuerza: La construcción de legitimidad en la Selva Lacandona”, in Emiliano Buis (dir.), ¿Justificar la guerra? Discursos y prácticas en torno a la legitimación del uso de la fuerza y su licitud en el Derecho Internacional, Eudeba, Buenos Aires, 2014, pp. 241–242.

10 A.-M. La Rosa and C. Wuerzner, above note 2, pp. 332–333. See also Sivakumaran, Sandesh, “Lessons for the Law of Armed Conflict from Commitments of Armed Groups: Identification of Legitimate Targets and Prisoners of War”, International Review of the Red Cross, Vol. 93, No. 882, 2011, p. 463CrossRefGoogle Scholar.

11 Sassòli, Marco, “Taking Armed Groups Seriously: Ways to Improve their Compliance with International Humanitarian Law”, Journal of International Humanitarian Legal Studies, No. 1, 2010, p. 30Google Scholar. See also Aïvo, Gérard, “Le Rôle des Accords Spéciaux dans la Rationalisation des Conflits Armés Non Internationaux”, Revue québécoise de droit international, No. 27.1, 2014, pp. 23–30Google Scholar.

12 CA3. A similar provision can be found in the 1954 Hague Convention for the Protection of Cultural Property in the Event of Armed Conflict, Article 19(2). Although our analysis is focused on CA3, we believe it would also be applicable to special agreements under the 1954 Hague Convention. However, even if Article 19(2) of the 1954 Hague Convention did not exist, the parties to NIACs could still reach agreements concerning the protection of cultural property based solely on the text of CA3.

13 A special agreement exclusively between AGs can be envisaged taking into account that an armed conflict “exists whenever there is a resort to armed force between States or protracted armed violence between governmental authorities and organized armed opposition groups or between such groups within a State” (emphasis added). International Criminal Tribunal for the former Yugoslavia (ICTY), The Prosecutor v. Tadić, Case No. IT-94-1, Decision on the Defence Motion for Interlocutory Appeal on Jurisdiction (Appeals Chamber), 2 October 1995, para. 70.

14 Cessation of Hostilities Framework Agreement between Government of the Republic of Indonesia and the Free Aceh Movement, 9 December 2002 (Indonesia Agreement), available at: www.usip.org/sites/default/files/file/resources/collections/peace_agreements/aceh_12092002.pdf; Humanitarian Ceasefire Agreement on the Conflict in Darfur, 2 April 2004, available at: http://peacemaker.un.org/sites/peacemaker.un.org/files/SD_040408_Humanitarian%20Ceasefire%20Agreement%20on%20the%20Conflict%20in%20Darfur.pdf; Protocol on the Establishment of Humanitarian Assistance in Darfur, 8 April 2004, available at: http://peacemaker.un.org/sites/peacemaker.un.org/files/SD_040408_Humanitarian%20Ceasefire%20Agreement%20on%20the%20Conflict%20in%20Darfur.pdf.

15 General Agreement Signed in Addis Ababa on 8 January 1993, available at: www.usip.org/sites/default/files/file/resources/collections/peace_agreements/somalia_01081993_gen.pdf; Agreement on Implementing the Cease-Fire and on Modalities of Disarmament (Supplement to the General Agreement Signed in Addis Ababa on 8 January 1993), available at: www.usip.org/sites/default/files/file/resources/collections/peace_agreements/somalia_01081993_sup.pdf; Acuerdo político entre el FMLN y la Juventud Militar para la constitución del nuevo ejército, 1981, available at: http://www.cedema.org/ver.php?id=4788. Sivakumaran mentions the 2008 Acte d'engagement concluded in the Democratic Republic of the Congo as an agreement between AGs. Although it is true that AGs undertake most of the commitments in the agreement and that the government is initially only referred to as a facilitator, Article 4 establishes specific obligations upon the Government. Hence, it is not clear to what extent the Acte d'engagement can be considered as exclusively concluded between armed groups. Sandesh Sivakumaran, The Law of Non-International Armed Conflicts, Oxford University Press, Oxford, 2012, p. 133; Acte d'engagement, 2008, available at: www.essex.ac.uk/armedcon/story_id/000720.pdf.

16 Of course, ceasefire agreements and peace agreements may also include provisions that do not deal with humanitarian concerns. However, this prevents neither their consideration as special agreements, nor their regulation under international law, as will be argued in the second part of this paper.

17 For example, in a ceasefire agreement concluded in 2002 between the government of Angola and UNITA, it was established that “[t]he task of re-establishing a cease-fire encompasses … [t]he guarantee of protection for people and their possessions, of resources and public assets, as well as the free circulation of persons and goods”. Cease Fire Agreement between Angola Government and UNITA, 4 April 2002 (Angola Agreement), available at: www.refworld.org/cgi-bin/texis/vtx/rwmain?docid=3e81949e4. In the case of peace agreements, references to IHL “most commonly pertain to the provisions of the law that continue to apply, or that come into force, after the cessation of hostilities …. [S]uch commitments have included … the release of ‘prisoners of war’ or detainees belonging to the respective parties (e.g. in Angola, Bosnia and Herzegovina, Cambodia, Côte d'Ivoire, Liberia, and Sierra Leone), the duties of the parties towards evacuated, displaced and interned civilians (e.g. in Cambodia), the respective duties of military and civilian authorities to account for missing and dead members of armed formations and civilians (e.g. Rwanda, Bosnia and Herzegovina), and the duty of the parties to report the location of landmines (e.g. Rwanda).” ICRC, Increasing Respect for International Humanitarian Law in Non-International Armed Conflicts, Geneva, February 2008, p. 26, available at: www.icrc.org/eng/assets/files/other/icrc_002_0923.pdf. Another agreement containing humanitarian provisions is the 1993 Cotonu Agreement between the Interim Government of National Unity of Liberia, the National Patriotic Front of Liberia and the United Liberation Movement of Liberia for Democracy, which deals, for example, with the release of prisoners of war and detainees (Article 10), humanitarian assistance (Article 17) and repatriation of refugees (Article 18). Cotonu Agreement, 25 July 1993, available at: www.refworld.org/docid/3ae6b5796.html.

18 For example, the Deed of Commitment signed between the non-governmental organization Geneva Call and the Puntland State of Somalia. Geneva Call, Deed of Commitment under Geneva Call of Adherence to a Total Ban on Anti-Personnel Mines and for Cooperation in Mine Action, Puntland State of Somalia, reproduced in Marco Sassòli, Antoine Bouvier and Anne Quintin, How Does Law Protect in War?, Vol. 3, ICRC, Geneva, 2011, pp. 1706–1708, available at: www.icrc.org/casebook/doc/case-study/geneva-somalia-mines-case-study.htm.

19 Jean Pictet (ed.), Commentary on the Geneva Conventions of 12 August 1949, Vol. 1: Geneva Convention for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, ICRC, Geneva, 1952, pp. 59–60. The author refers to “bilateral agreements” which “will generally only be concluded because of an existing situation which neither of the parties can deny, no matter what the legal aspect of the situation may in their opinion be”. Nevertheless, in our opinion, the fact that agreements between a single party to the conflict and other entities are not framed by CA3 does not mean that they have no legal value within the international realm. Quite the contrary, they may serve the important purpose of reaffirming and/or enabling compliance with international obligations.

20 In the Commentary to GC I, Pictet affirms that the parties are “under an obligation to try to bring about a fuller application of the Convention by means of a bilateral agreement” (emphasis added): ibid., p. 59. This means that they must make an effort to reach an agreement. If this were not the case, it would seem improbable to think that a State would feel itself obliged to negotiate a special agreement with an AG, especially since these groups are by definition in breach of domestic law.

21 ICRC, Improving Compliance with International Humanitarian Law – ICRC Expert Seminars, Report, October 2003, pp. 20–21, available at: www.icrc.org/eng/assets/files/other/improving_compliance_with_international_report_eng_2003.pdf; Bangerter, Olivier, “Reasons Why Armed Groups Choose to Respect International Humanitarian Law or Not”, International Review of the Red Cross, Vol. 93, No. 882, 2011, p. 357CrossRefGoogle Scholar.

22 S. Sivakumaran, above note 10, p. 464.

23 On the principle of equality of belligerents, see Greenwood, Christopher, “The Relationship between Ius ad Bellum and Ius in Bello”, Review of International Studies, No. 9, 1983, pp. 221–234CrossRefGoogle Scholar. Interestingly, Somer argues that the term “equality” is a narrow concept and proposes to use instead “parity”, which better represents a general equality of status. See J. Somer, above note 2, pp. 661–662.

24 See Henckaerts, Jean-Marie, “Binding Armed Opposition Groups through Humanitarian Treaty Law and Customary Law”, Collegium, No. 27, 2003, pp. 126–127Google Scholar; and L. Moir, above note 2, pp. 54–55.

25 Other unsolved situations are mentioned by J. Somer, above note 2, p. 661; and L. Moir, above note 2, pp. 55–56.

26 Cassese, Antonio, “The Status of Rebels under the 1977 Geneva Protocol on Non-International Armed Conflicts”, International and Comparative Law Quarterly, Vol. 30, No. 2, 1981, pp. 429–430CrossRefGoogle Scholar.

27 Such argumentation is presented in J. Pictet, above note 19, p. 51; and Jean Pictet (ed.), Commentary on the Geneva Conventions of 12 August 1949, Vol. II: Geneva Convention for the Amelioration of the Condition of the Wounded, Sick and Shipwrecked Members of Armed Forces at Sea, ICRC, Geneva, 1960, p. 34. Additional explanations and critiques can be found in Jean d'Aspremont and Jérôme de Hemptinne, Droit international humanitaire, Pedone, Paris, 2012, pp. 98–99; and historically in A. Cassese, above note 26, p. 416; and Erik Castrén, Civil War, Soumalainen Tiedeakatemia, Helsinki, 1966, p. 154.

28 J. Somer, above note 2, pp. 661–662. See also Kleffner, Jann, “The applicability of international humanitarian law to organized armed groups”, International Review of the Red Cross, Vol. 93, No. 882, 2011, pp. 443–461CrossRefGoogle Scholar.

29 M. Sassòli, above note 11, p. 13.

30 J. Somer, above note 2, p. 662.

31 S. Sivakumaran, above note 15, p. 243.

32 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 Schmitt and Jelena Pejić (eds.), International law and Armed Conflict: Exploring the Faultlines, Martinus Nijhoff, Leiden and Boston, MA, 2007, p. 246.

33 Cedric Ryngaert, “Non-State Actors in International Humanitarian Law”, in Jean d'Aspremont (ed.), Participants in the International Legal System: Multiple Perspectives on Non-State Actors in International Law, Routledge, Oxon, 2011, p. 288.

34 See ICRC, above note 17, p. 16.

35 Bosnia and Herzegovina, Agreement No. 1, 22 May 1992 (1992 Agreement), reproduced in M. Sassòli, A. Bouvier and A. Quintin, above note 18, pp. 1717–1721, and available at: www.icrc.org/casebook/doc/case-study/yugoslavia-agreements-case-study.htm.

36 Nairobi Peace Agreement, 17 December 1985, available at: http://theirwords.org/?country=UGA&ansa=109&document_type=1

37 Acte d'engagement, above note 15.

38 S. Sivakumaran, above note 10, p. 471.

39 Interestingly, Bangerter explains that in order to get AGs to respect IHL “or to respect it better, we need to understand the factors that influence their choices”. Thus, “[r]espect for IHL can only be encouraged – and hence improved – if the reasons used by armed groups to justify respect or lack of it are understood and if the arguments in favour of respect take those reasons into account”. See O. Bangerter, above note 21, pp. 354, 383.

40 See Muñoz-Rojas, Daniel and Frésard, Jean-Jacques, “The Roots of Behaviour in War: Understanding and Preventing IHL Violations”, International Review of the Red Cross, Vol. 86, No. 853, 2003, pp. 192, 203Google Scholar.

41 See ICRC, above note 17, p. 16.

42 In order to asses precisely what rules were previously binding, it should be taken into consideration whether AP II – with its more restricted scope of application – was already in force between the parties to the conflict, or if the conflict was only regulated by CA3.

43 Afghan Peace Accord (Islamabad Accord), 7 March 1993, available at: www.incore.ulst.ac.uk/services/cds/agreements/pdf/afgan1.pdf; Peace Accords for Angola, May 1991, available at www.incore.ulst.ac.uk/services/cds/agreements/pdf/ang1.pdf; Acte d'engagement, above note 15; Agreement on Cessation of Hostilities and Peaceful Settlement of Conflict between the Armed Forces of Liberia and the National Patriotic Front of Liberia and the Independent National Patriotic Front of Liberia, 24 October 1990, available at: www.ucdp.uu.se/gpdatabase/peace/Lib%2019901024.pdf; Agreement between the President of the Republic of Tajikistan, E. S. Rakhmonov, and the Leader of the United Tajik Opposition, S. A. Nuri, on the Results of the Meeting Held in Moscow on 23 December 1996, available at: http://theirwords.org/media/transfer/doc/1_tj_uto_1996_03-787be4c90d0af3748b7c4630429c01b7.pdf; Nairobi Peace Agreement, above note 36.

44 Memorandum of Understanding of 27 November 1991, reproduced in M. Sassòli, A. Bouvier and A. Quintin, above note 18, pp. 1713–1717, and available at: www.icrc.org/casebook/doc/case-study/yugoslavia-agreements-case-study.htm.

45 1992 Agreement, above note 35.

46 L. Moir, above note 2, p. 127; Bugnion, François, “Jus ad Bellum, Jus in Bello and Non-International Armed Conflicts”, Yearbook of International Humanitarian Law, Vol. 6, 2003, p. 193CrossRefGoogle Scholar.

47 ICTY, The Prosecutor v. Enver Hadzihasanovic and Amir Kubura, Case No. IT-01-47-AR73.3, Decision on Joint Defence Interlocutory Appeal of Trial Chamber on Rule 98bis Motion for Acquittal (Appeals Chamber), 11 March 2005, para. 28, fn. 51. For how the ICTY has used special agreements, see Luisa Vierucci, “‘Special Agreements' between Conflicting Parties in the Case-Law of the ICTY”, in Bert Swart, Alexander Zahar and Goran Sluiter (eds), The Legacy of the International Criminal Tribunal for the Former Yugoslavia, Oxford University Press, Oxford, 2011, pp. 401–433.

48 See, for example, Agreement on a Ceasefire between the Government of the Democratic Socialist Republic of Sri Lanka and the Liberation Tiers of Tamil Eelam, 22 February 2002 (Sri Lanka Agreement), available at: www.regjeringen.no/nb/dokumentarkiv/Regjeringen-Bondevik-II/ud/Lover-og-regler/2002/agreement_on_a_ceasefire_between.html?id=260701; Indonesia Agreement, above note 14; Angola Agreement, above note 17.

49 In this agreement, among other relevant provisions, the parties “decided to free all the prisoners of war and all other persons detained because of the armed conflict in Darfur” and undertook “to facilitate the delivery of humanitarian assistance and the creation of conditions favorable to supplying emergency relief to the displaced persons and other civilian victims of war and this, wherever they are in the Darfur region, in accordance with the appendix attached to the present Agreement”. Humanitarian Ceasefire Agreement on the Conflict in Darfur, above note 14.

50 Protocol on the Establishment of Humanitarian Assistance in Darfur, above note 14.

51 S. Sivakumaran, above note 15, p. 125. Still, the legal basis for the inclusion of human rights obligations in special agreements can be disputed. See different arguments in L. Zegveld, above note 3, p. 50; and L. Moir, above note 2, p. 64.

52 In the Philippines, the government and the National Democratic Front of the Philippines devoted an entire part of a special agreement, composed of thirteen articles, to “respect for human rights”, addressing such matters as the right to life, the prohibition of summary executions, and involuntary disappearances. Comprehensive Agreement on Respect for Human Rights and International Humanitarian Law between the Government of the Republic of the Philippines and the National Democratic Front of the Philippines, 16 March 1998 (Philippines Agreement), available at: http://theirwords.org/media/transfer/doc/ph_ndfp_1998_17-ef3249df335f48cd378d1c5082457be4.pdf. In Sierra Leone, the parties addressed political and civil liberties, with reference to other international human rights law instruments, in Article 19 of the Peace Agreement between the Government of the Republic of Sierra Leone and the Revolutionary United Front of Sierra Leone, 30 November 1996, available at: http://theirwords.org/media/transfer/doc/1_sl_ruf_1996_03-e377977056bb4bc499dfaa593507511d.pdf.

53 Ewumbue-Monono, Churchill, “Respect for International Humanitarian Law by Armed Non-State Actors in Africa”, International Review of the Red Cross, Vol. 88, No. 864, 2006CrossRefGoogle Scholar.

54 A.-M. La Rosa and C. Wuerzner, above note 2, pp. 332–333. See also S. Sivakumaran, above note 10, p. 464.

55 For example, the Protocol on the Establishment of Humanitarian Assistance in Darfur, above note 14.

56 L. Moir, above note 2, pp. 86–87, 274.

57 This may counter the argument of reciprocity that is sometimes used to justify IHL violations. D. Muñoz-Rojas and J.-J. Frésard, above note 40, p. 202.

58 Arai-Takahashi deals with similar issues during IACs. Based on Article 47 of GC IV, he explains that “the rights of protected persons in an occupied territory must not be derogated from by … an agreement entered into by parties to the conflict. This provision prohibits only negative derogation (la derogation négative). It does not prevent parties from entering into agreements to broaden the ambit of rights for protected persons (la dérogation positive).” See Yutaka Arai-Takahashi, The Law of Occupation: Continuity and Change of International Humanitarian Law, and its Interaction with International Human Rights Law, Martinus Nijhoff, Leiden and Boston, MA, 2009, p. 273.

59 See ICJ, above note 5, para. 218. The question remains, though, as to what extent special agreements can modify rules of other international treaties, such as AP II when applicable, or even customary rules. In the context of IACs, certain provisions attempt to address this matter: Article 6 of GCs I, II and III and Article 7 of GC IV all prohibit any special agreement that may adversely affect the situation of the wounded, sick, shipwrecked, prisoners of war, and medical and religious personnel. Article 10(5) of GCs I, II and III and Article 11(5) of GC IV also forbid certain derogations by special agreements. See also François Bugnion, Le Comité International de la Croix-Rouge et la protection des victimes de la guerre, ICRC, Geneva, 1994, pp. 502–504.

60 D. Muñoz-Rojas and J.-J. Frésard, above note 40, pp. 193–195, 203–204.

61 Ibid., pp. 203–204.

62 J. Somer, above note 2.

63 Certainly, there have been some discussions on the possible deterrent effect of such mechanisms, especially considering that preambular para. 5 of the Statute of the International Criminal Court establishes that the parties are “[d]etermined to put an end to impunity for the perpetrators of these crimes and thus to contribute to the prevention of such crimes”. This view has been supported, for example, by Cassese and Falk: see Antonio Cassese, International Criminal Law, Oxford University Press, Oxford, 2008, p. 440; Richard Falk, The Declining World Order: America's Imperial Geopolitics, Routledge, New York and London, 2004, p. 120. However, this effect has been questioned in Theodore Meron, The Humanization of International Law, Martinus Nijhoff, The Hague, 2006, pp. 179–180. See also ICRC, Ad Hoc Tribunals, available at: www.icrc.org/eng/war-and-law/international-criminal-jurisdiction/ad-hoc-tribunals/overview-ad-hoc-tribunals.htm. Crawford has explained that “[t]he deterrent effect of international prosecution is unclear, and probably always will be”: James Crawford, Brownlie's Principles of Public International Law, Oxford University Press, Oxford, 2012, p. 690. For a continuation of the discussion on the deterrent effect of international criminal justice, see the debate between Chirs Jenks and Guido Acquaviva in this issue of the Review.

64 In Darfur, the government of Sudan, the Sudan Liberation Movement/Army and the Sudan Justice and Equality Movement created a commission in charge of “receiving, verifying, analyzing, and judging complaints related to the possible violations of the cease fire” and “developing adequate measures to guard against such incidents in the future”. See Humanitarian Ceasefire Agreement on the Conflict in Darfur, above note 14. In Sri Lanka, the 2002 agreement between the government and the Liberation Tigers of Tamil Eelam included the creation of the Sri Lanka Monitoring Mission “to enquire into any instance of violation of the terms and conditions of this Agreement”: Sri Lanka Agreement, above note 48. In Indonesia, the government and the Free Aceh Movement reactivated a previously created Joint Security Committee and established that part of its functions was “to undertake full investigation of any security violations” and “to take appropriate action to restore the security situation and to agree beforehand on the sanctions to be applied, should any party violate this Agreement”. Indonesia Agreement, above note 14.

65 Hersch Lauterpacht (ed.), International Law: A Treatise, Vol. 2: Disputes, War and Neutrality, Longmans, Green and Co., London, New York and Toronto, 1952, pp. 226–233; Fritz Kalshoven and Liesbeth Zegveld, Constraints on the Waging of War: An Introduction to International Humanitarian Law, ICRC and Cambridge University Press, Geneva, 2001, pp. 15–18.

66 “In international law, the problem of the subject appears in the designation of states as ‘subjects’ of the law while individuals and corporations are regarded as ‘objects’ of the law…whatever rights or duties individuals and corporations have are derivative of, and enforceable only by states who, as ‘subjects’, conferred these rights and duties upon them”: A. Claire Cutler, “Critical Reflections on the Westphalian Assumptions of International Law and Organization: A Crisis of Legitimacy”, in Andrea Bianchi (ed.) Non-State Actors and International Law, Ashgate, Aldershot, 2009, p. 22. See also Higgins, Rosalyn, “International Law and the Avoidance, Containment and Resolution of Disputes: General Course on Public International Law”, Recueils des cours de l'Académie de droit international, Vol. 230, 1991, pp. 79–81Google Scholar.

67 For a similar analysis on individuals, see ibid.; and Roland Portmann, Legal Personality in International Law, Cambridge University Press, New York, 2010, p. 42.

68 Jean Pictet (ed.), Commentary on the Geneva Conventions of 12 August 1949, Vol. 3: Geneva Convention relative to the Treatment of Prisoners of War, ICRC, Geneva, 1960, p. 44. According to Pictet in the Commentary to GC I, this provision was caused by States' fear that its application may interfere with their right to lawfully suppress AGs. Furthermore, it was not intended to “constitute any recognition by the de jure Government that the adverse Party has authority of any kind” or “to give [that party] any right to special protection or any immunity, whatever it may be and whatever title it may give itself or claim”. See J. Pictet (ed.), above note 19, p. 60.

69 Constitutional Court of Colombia, Constitutional Conformity of Protocol II, Case No. C-225/95, 18 May 1995 (unofficial translation), partly reproduced in M. Sassòli, A. Bouvier and A. Quintin, above note 18, p. 2245, para. 17, and available in Spanish at: www.corteconstitucional.gov.co/relatoria/1995/c-225-95.htm.

70 See SCSL, Kallon and Kamara, above note 4, paras 45–50.

71 The SCSL had the opportunity to do so in the Kallon and Kamara case, above note 4. However, it limited itself to stating that the agreement did not need to be considered as an international treaty in order to create rights and obligations under municipal law, while expressly deciding not to analyze the validity of the agreement under municipal law, as that was not questioned before the Court.

72 J. Somer, above note 2, pp. 659–660.

73 This would raise a number of complex questions concerning the actors entitled to bring cases before national courts using special agreements as a legal basis and regarding the specific commitments that could entail State or individual responsibility. In any case, given the asymmetrical relationship described in this section, it does seem improbable that national judges would hold States accountable for violations of those agreements.

74 M. Sassòli, above note 11, p. 23.

75 Antonio Cassese and Luigi Condorelli, “Is Leviathan Still Holding Sway over International Dealings?”, in Antonio Cassese, Realizing Utopia: The Future of International Law, Oxford University Press, Oxford, 2012, p. 21.

76 Rondeau, Sophie, “Participation of Armed Groups in the Development of the Law Applicable to Armed Conflicts”, International Review of the Red Cross, Vol. 93, No. 883, 2011, p. 669CrossRefGoogle Scholar.

77 On the link between the definition of NIACs and the elements that determine the existence of an AG, see generally Michael Schmitt, “The Status of Opposition Fighters in a Non-International Armed Conflict”, in Kenneth Watkin and Andrew Norris (eds), Non-International Armed Conflict in the Twenty-First Century, International Law Studies, Vol. 88, Naval War College, Newport, RI, 2012, pp. 119–144.

78 For the purposes of this paper, transnational law refers to the law which regulates actions that transcend national frontiers without being “purely domestic nor purely international, but rather, a hybrid of the two”. See Koh, Harold Hongju, “Why Transnational Law Matters”, Keynote at AALS Workshop on Integrating Transnational Legal Perspectives into the First-Year Curriculum, 3–7 January 2006, Penn State International Law Review, No. 24, 2006, p. 745Google Scholar.

79 M. Sassòli, above note 11, p. 23.

80 A. Cassese and L. Condorelli, above note 75 (emphasis in original). The authors do not explain in great detail what exactly these spaces are, but they do suggest that “work is in progress on several fronts, with instruments of all types, both hard and soft, and within the framework of various international organizations (UN, International Labour Organization, Organization for Economic Co-Operation and Development, European Union, UNIDROIT, etc.). This is, for example, the case in the fields of development cooperation, the fight against corruption, corporate social responsibility, environment protection, promotion of virtuous human rights practices by multinational companies, identification of mandatory rules the lex mercatoria must respect, and so on.”

81 O. Bangerter, above note 21, pp. 360–361.

82 See, for example, Memorandum of Understanding, above note 42; 1992 Agreement, above note 35; Philippines Agreement, above note 52.

83 As expressed in Article 38 of the Statute of the ICJ, the undisputed sources of international law are international conventions, international customary law and general principles of law. See generally Malcolm M. Shaw, International Law, 6^th ed., Cambridge University Press, Cambridge, 2008, pp. 113–122.

84 Vienna Convention on the Law of Treaties, 23 May 1969, 1155 UNTS 331 (entered into force 27 January 1980).

85 International Law Commission, Yearbook of the International Law Commission: 1962, Vol. 2, United Nations, New York, 1964, p. 162, Art. 1, Commentary 8.

86 Ibid., p. 164.

87 When giving the definitions relevant to understanding its scope, Article 1.a of the VCLT affirms that “‘treaty’ means an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation” (emphasis added). Vienna Convention on the Law of Treaties, above note 84, Art. 1.

88 Ibid., Art. 3.

89 See above note 52.

90 R. Portmann, above note 67, pp. 212–213.

91 Rosalyn Higgins, Problems and Process: International Law and How We Use It, Clarendon Press, Oxford, 1994, p. 2.

92 See above note 83 in reference to those sources that can be understood as typical.

93 As explained by Portmann, all these interactions “cumulate in decisions which themselves enjoy authority not because international rules exist to this effect, but because the relevant participants effectively accept, to varying degrees in different contexts, the decision as compulsory”. R. Portmann, above note 67, pp. 211–212.

94 R. Portmann, above note 67, pp. 267–268, and in general, pp. 264–268.

95 C. Ryngaert, above note 33, pp. 288–289. See also ICRC Customary Law Study, above note 6, pp. xxxiv–lvii; and J.-M. Henckaerts, above note 24, p. 128.

96 R. Portmann, above note 67, p. 264. This is a relevant critique, as “certain rules of international humanitarian law are considered almost unanimously to be peremptory norms of international law”. Rafael Nieto-Navia, “International Peremptory Norms (Jus Cogens) and International Humanitarian Law”, The Hague, 2001, p. 20, available at www.iccnow.org/documents/WritingColombiaEng.pdf.

97 C. Ryngaert, above note 33, p. 289.

98 R. Higgins, above note 66, p. 47.

99 Ibid., p. 48.

100 See, among others, Pejić, Jelena, “Non-Discrimination and Armed Conflict”, International Review of the Red Cross, Vol. 83, No. 841, 2001Google Scholar, available at: https:// www.icrc.org/eng/resources/documents/misc/57jqzq.htm; R. Nieto-Navia, above note 96, pp. 25–26; ICTY, The Prosecutor v. Kupreškic et al., Case No. IT-95-16-T, Judgment (Trial Chamber), 14 January 2000, para. 520.

101 See above notes 44 and 52.

102 We are referring here to some substantial rules such as the pacta sunt servanda clause (Art. 26), the general rules of interpretation (Art. 31) and the rules concerning conflicts with peremptory norms (Arts 53 and 64). VCLT, above note 84.

103 ICTR, The Prosecutor v. Bagosora et al., Case No. ICTR-98-37-A, Decision on the Admissibility of the Prosecutor's Appeal from the Decision of a Confirming Judge Dismissing an Indictment against Théoneste Bagosora and 28 Others (Appeals Chamber), 8 June 1998, para. 28; ICTY, The Prosecutor v. Erdemović, Case No. IT-96-22-A, Joint Separate Opinion of Judge McDonald and Judge Vohrah (Appeals Chamber), 7 October 1997, para. 3; ICTY, The Prosecutor v. Hadžihasanović et al., Case No. IT-01-47-PT, Decision on Joint Challenge to Jurisdiction (Trial Chamber), 12 November 2002, para. 63; STL, Interlocutory Decision on the Applicable Law: Terrorism, Conspiracy, Homicide, Perpetration, Cumulative Charging, Case No. STL-11-01/I/AC/R176 bis, 16 February 2011, para. 26.

104 On the challenges and stakes inherent in defining certain phenomena as legal or non-legal, see Andrea Bianchi, “Reflexive Butterfly Catching: Insights from a Situated Catcher”, in Joost Pauwelyn, Ramses Wessel and Jan Wouters (eds), Informal International Lawmaking, Oxford University Press, Oxford, 2012, p. 200. See also Heffes, Ezequiel, “The Responsibility of Armed Opposition Groups for Violations of International Humanitarian Law: Challenging the State-Centric System of International Law”, Journal of International Humanitarian Legal Studies, Vol. 4, No. 1, 2013, pp. 81–107CrossRefGoogle Scholar. There, the author explores the possible application of the International Law Commission's Draft Articles on the Responsibility of States for Internationally Wrongful Acts (2001) to wrongful acts committed by members of an AG so as to attribute them to the AG as such.