1 This article does not address potential responsibilities that might exist in relation to extraterritorial States providing support to community defence groups. The principles of attribution discussed in the second section of the article could similarly extend to extraterritorial States, but extraterritoriality adds additional complexities of jurisdictional scope in relation to IHL and IHRL that are not addressed here.

2 See definition and background on secondary rules in Milanovic, Marko, “Special Rules of Attribution of Conduct in International Law”, International Law Studies, Vol. 96, 2020, p. 300Google Scholar. See also Kress, Claus, “L'organe de facto en droit international public: Réflexions sur l'imputation a l'Etat de l'acte d'un particulier a la lumiere des developpments recents”, Revue Générale de Droit International Public, Vol. 105, No. 1, 2001, pp. 123–124Google Scholar.

3 See, for example, the discussion in relation to the Shabbiha in Syria and the Popular Mobilization Force in Iraq, in Maddocks, Jennifer, “Outsourcing of Governmental Functions in Contemporary Conflict: Rethinking the Issue of Attribution”, Virginia Journal of International Law, Vol. 59, No. 1, 2019, pp. 80–82Google Scholar.

4 “Boko Haram” is not a label used by the group itself but is commonly used in media reporting to refer to the armed group People Committed to the Propagation of the Prophet's Teachings and Jihad, or, less often, to the Islamic State West Africa Province. For more information, see International Crisis Group, Facing the Challenge of the Islamic State in West Africa Province, Africa Report No. 273, 16 May 2019, available at: www.crisisgroup.org/africa/west-africa/nigeria/273-facing-challenge-islamic-state-west-africa-province (all internet references were accessed in July 2021).

5 International Crisis Group, Watchmen of Lake Chad: Vigilante Groups Fighting Boko Haram, Africa Report No. 244, 23 February 2017, p. 4, available at: https://reliefweb.int/sites/reliefweb.int/files/resources/244-watchmen-of-lake-chad-vigilante-groups-fighting-boko-haram.pdf.

6 Ibid., p. 4.

7 Agbiboa, Daniel E., “The Precariousness of Protection: Civilian Defense Groups Countering Boko Haram in Northeastern Nigeria”, African Studies Review, Vol. 64, No. 1, 2020, p. 204Google Scholar. See also International Crisis Group, above note 5, p. 6.

8 Pratten, David, “The Politics of Protection: Perspectives on Vigilantism in Nigeria”, Journal of the International African Institute, Vol. 78, No. 1, 2008, p. 4CrossRefGoogle Scholar.

9 Schuberth, Moritz, “The Challenge of Community-Based Armed Groups: Towards a Conceptualization of Militias, Gangs, and Vigilantes”, Contemporary Security Policy, Vol. 36, No. 2, 2015, p.299CrossRefGoogle Scholar. See also D. Pratten, above note 8, p. 6, on the link between vigilantism and the “politics of belonging”.

10 Jok Madut Jok, Mareike Schomerus, Luka Biong Deng Kuol, Ingrid Marie Breidlid and Michael J Arensen, Informal Armies: Community Defence Groups in South Sudan's Civil War, Saferworld, February 2017, p. 3, available at: www.saferworld.org.uk/resources/publications/1108-informal-armies-community-defence-groups-in-south-sudanas-civil-war.

11 See the definition of private military and security companies provided at para. 9 of the Preface to the Montreux Document on Pertinent International Legal Obligations and Good Practices for States related to Operations of Private Military and Security Companies during Armed Conflict, International Committee of the Red Cross (ICRC), Geneva, August 2009 (Montreux Document), available at: www.eda.admin.ch/dam/eda/en/documents/aussenpolitik/voelkerrecht/20192511-montreux-document_EN.pdf.

12 Johnston, Les, “What is Vigilantism?”, British Journal of Criminology, Vol. 36, No. 2, 1996, pp. 229–230CrossRefGoogle Scholar. In the present article, the term “community defence group” is preferred over “vigilantes” because in common parlance, and in some academic works, vigilantism is defined to exclude actors that operate with the support of the State. This is too narrow for our purposes. Many community defence groups are supported by the State, precisely because of their overlapping interests in protecting communities. See, for example, Chris A. M. Kwaja, “Non-State Armed Groups in Adamawa State”, in Freedom C. Onuoha and Chris A. M. Kwaja (eds), Non-State Armed Groups in North East Nigeria: Challenges and Opportunities for Security Sector Governance, Cleen Foundation, 2018, pp. 21–22, available at: https://cleen.org/wp-content/uploads/2018/12/Armed-Groups-in-North-East-Nigeria-Challenges-and-Opportunities-for-Security-Sector-Governance.pdf; D. E. Agbiboa, above note 7, p. 8.

13 L. Johnston, above note 12, p. 229.

14 J. M. Jok et al., above note 10, pp. 3–4; Carlo Koos, “Why and How Civil Defense Militias Emerge: The Case of the Arrow Boys in South Sudan”, Studies in Conflict and Terrorism, Vol. 37, No. 12, 2014, p. 1047. In relation to the establishment of the Volunteers for the Defence of the Homeland, in Burkina Faso, see Claire Zutterling, “Armer les civils: La loi des Volontaires pour la défense de la patrie au Burkina Faso”, GRIP, 30 October 2020, available at: https://grip.org/https-grip-org-armer-civils-burkina-faso/.

15 M. Schuberth, above note 9, p. 303. In practice, it can be difficult to separate the motivation of groups. See, for example, Johnston's discussion of vigilantism as a reaction to crime and social deviance, and the complex overlaps that can exist with social control vigilantism, or even vigilantism seeking political power: L. Johnston, above note 12, pp. 228–230. David Pratten notes the disbanding of the O'odua People's Congress and Bakassi Boys due to their promotion of political agendas, but also notes the reality of vigilante groups as a means for “poor, unemployed youth” to “insert themselves within political and economic niches of the state apparatus”: D. Pratten, above note 8, pp. 5, 7.

16 C. A. M. Kwaja, above note 12.

17 Lucian Harriman with Ilona Drewy and David Deng, “Like the Military of the Village”: Security, Justice and Community Defence Groups in South-East South Sudan, Saferworld, February 2020, p. 11, available at: www.saferworld.org.uk/resources/publications/1245-alike-the-military-of-the-villagea-security-justice-and-community-defence-groups-in-south-east-south-sudan.

18 Ibid., pp. 24–28.

19 L. Johnston, above note 12, p. 220.

20 We are thus considering a broader category of actors than “community-embedded armed groups” per the ICRC's Roots of Restraint in War study, which is limited to groups that “lack an organizational structure and responsible command necessary to be considered an armed group under IHL”. ICRC, The Roots of Restraint in War, Geneva, 2018, p. 54, available at: www.icrc.org/en/publication/4352-roots-restraint-war.

21 J. M. Jok et al., above note 10, p. 21. See also the discussion on the “historical and spiritual legitimacy” of Nigerian vigilantism in D. Pratten, above note 8, p. 9; Kyle Dietrich, “When We Can't See the Enemy, Civilians Become the Enemy”: Living Through Nigeria's Six-Year Insurgency, Center for Civilians in Conflict, 2015, pp. 57–58, available at: https://civiliansinconflict.org/wp-content/uploads/2015/10/NigeriaReport_Web.pdf; C. Zutterling, above note 14.

22 See, for example, C. A. M. Kwaja, above note 12, p. 21; J. M. Jok et al., above note 10, p. 9.

23 For example, the Dozo or Traditional Hunters Society in Mali was said to employ hunting weapons and traditional magic against armed insurgent groups: Corinne Dufka, “We Used to Be Brothers”: Self-Defense Group Abuses in Central Mali, Human Rights Watch, 2018, available at: https://www.hrw.org/report/2018/12/07/we-used-be-brothers/self-defense-group-abuses-central-mali. See also Sam Mednick, “Victims or Villains? The Volunteer Fighters on Burkina Faso's Front Line”, The New Humanitarian, 12 October 2020, available at: www.thenewhumanitarian.org/news-feature/2020/10/12/Burkina-Faso-conflict-jihadist-vigilante-volunteer-fighters; D. E. Agbiboa, above note 7, pp. 9, 12.

24 The existence of non-State accountability mechanisms of community defence groups varies from context to context. For example, the ICRC's Roots of Restraint in War study notes as sources of influence and authority over the cattle-keeping groups of South Sudan (e.g. the Titweng and Gelweng discussed above) the role of chiefs and divine authority, in addition to politico-military elites: ICRC, above note 20, pp. 57–58. Community defence groups that are organized armed groups (as discussed below) by definition will have an internal means for regulating the conduct of their members: see International Criminal Tribunal for the former Yugoslavia (ICTY), Prosecutor v. Boškoski, Case No. IT-04-82-T, Judgment (Trial Chamber), 10 July 2008, para. 195.

25 A recent United Nations Mission in South Sudan (UNMISS) report, for example, indicated that “[c]ommunity-based militias were responsible for 78 percent of killings and injuries caused to civilians as well as abductions and conflict-related sexual violence during attacks in pockets of South Sudan”. UNMISS, “Community-Based Militias Responsible for 78% of Victims of Violence in South Sudan”, 31 March 2021, available at: https://tinyurl.com/4dnf4bfx. See also L. Harriman, I. Drewy and D. Deng, above note 17, p. 11; “Mali Attack: Behind the Dogon-Fulani Violence in Mopti”, BBC News, 25 March 2019, available at: www.bbc.com/news/world-africa-47694445; Michael L. Fleisher, “Sungusungu: State-Sponsored Village Vigilante Groups among the Kuria of Tanzania”, Africa, Vol. 20, No. 2, 2000, p. 223; ICRC, above note 20, p. 58; Amnesty International, “Burkina Faso: Witness Testimony Confirms Armed Group Perpetrated Mass Killings”, 20 March 2020, available at: www.amnesty.org/en/latest/news/2020/03/burkina-faso-witness-testimony-confirms-armed-group/; D. E. Agbiboa, above note 7, p. 18.

26 For example, military officers are said to have visited communities in order to encourage recruitment of people into the CJTF in 2013: see International Crisis Group, above note 5, p. 6. In recognition of the apparent effectiveness of the Arrow Boys’ response to the Lord's Resistance Army, US and Ugandan soldiers were said to have regularly consulted the group and “periodically furnished them with equipment in exchange for information”: J. M. Jok et al., above note 10, p. 9.

27 For example, the Borno Youth Empowerment Scheme provided some military training and uniforms to a select group of young men in the CJTF: see International Crisis Group, above note 5, pp. 5, 9.

28 For example, service in the Sungusungu of Nyaheiya, Tanzania was said to be compulsory: M. L. Fleisher, above note 25, p. 216; Heald, Suzette, “State, Law and Vigilantism in Northern Tanzania”, African Affairs, Vol. 105, No. 419, 2005, p. 273Google Scholar.

29 See, for example, J. M. Jok et al., above note 10, p. 9.

30 Romane Da Cunha Dupuy and Tanguy Quidelleur, Self-Defence Movements in Burkina Faso: Diffusion and Structuration of Koglweogo Groups, Noria, 15 November 2018, available at: www.noria-research.com/self-defence-movements-in-burkina-faso-diffusion-and-structuration-of-koglweogo-groups/; L. Harriman, I. Drewy and D. Deng, above note 17, p. 11.

31 Draft Articles on the Responsibility of States for Internationally Wrongful Acts, with Commentaries, in Report of the International Law Commission on the Work of Its Fifty-Third Session, UN Doc. A/56/10 (Yearbook of the International Law Commission, Vol. 2, No. 2), 2001 (Articles on State Responsibility), pp. 26–143, available at: https://legal.un.org/ilc/documentation/english/reports/a_56_10.pdf. The Articles on State Responsibility are not a treaty but nevertheless are widely relied upon as the articulation of customary international law in relation to State responsibility. See, for example, International Court of Justice (ICJ), Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia & Herzegovina v. Serbia & Montenegro), Judgment, 2007, ICJ Reports 2007 (Bosnian Genocide), paras 385, 398.

32 This article does not consider responsibility on the basis of conduct acknowledged and adopted by the State as its own. It would seem far-fetched that a State would ever accept and adopt as its own the type of conduct of community defence groups described in this article that would form the basis of the wrongful act.

33 Articles on State Responsibility, above note 31, Art. 4(1). The ICJ considered Article 4 as reflecting customary law: ICJ, Bosnian Genocide, above note 31, para. 385.

34 Articles on State Responsibility, above note 31, p. 40.

35 The Volunteers for the Defence of the Homeland, in Burkina Faso, warrants further study in this respect. A decree was passed in 2020 on the group's status that provides, inter alia, that the command of the group is assured by the command of the armed forces, and that the group benefits from the protection of the State in the execution of its missions. La loi portant institution des Volontaires de la défense de la Patrie, Decree No. 2020-0115, 12 March 2020, available at: https://tinyurl.com/kd76jwbv.

36 ICJ, Bosnian Genocide, above note 31, paras 392–393. See also ICJ, Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Judgment, 1986, ICJ Reports 1986, paras 109–114.

37 In relation to the relevance of the State's role in the creation of the group as a factor indicating control, see ICJ, Nicaragua, above note 36, paras 93–94; C. Kress, above note 2, pp. 106–107.

38 In relation to “incorporation”, Cameron and Chetail give the example whereby by act of contract, the State of Papua New Guinea purported to bestow upon members of a private security firm the status of “special constables”, a classification within the national police force. See Lindsey Cameron and Vincent Chetail, Privatizing War: Private Military and Security Companies under Public International Law, Cambridge University Press, Cambridge, 2013, pp. 140–141.

39 “Ohanaeze, Afenifere, ACF Disagree Over Civilian JTF's Recruitment into Army”, Punch, 13 November 2020, available at: https://punchng.com/ohanaeze-afenifere-acf-disagree-over-civilian-jtfs-recruitment-into-army/. See also International Crisis Group, Double-Edged Sword: Vigilantes in African Counter-Insurgencies, Africa Report No. 251, 7 September 2017, available at: www.crisisgroup.org/africa/west-africa/sierra-leone/251-double-edged-sword-vigilantes-african-counter-insurgencies.

40 M. L. Fleisher, above note 25, p. 210. Payments made to community defence group members (if any) who are not employed by the State vary between contexts. For example, the chairman of the Anambra Vigilante Services suggested that his members were paid only “a token amount”: see Human Rights Watch, The Bakassi Boys: The Legitimization of Murder and Torture, May 2002, available at: www.hrw.org/reports/2002/nigeria2/index.htm#TopOfPage. See also International Crisis Group, above note 5, p. 12.

41 International Crisis Group, above note 5, p. 21.

42 Ibid.

43 J. M. Jok et al., above note 10, pp. 4, 6, 23.

44 See the discussion on the relevance of domestic law in L. Cameron and V. Chetail, above note 38, p. 137. In practice, determining whether an employment relationship exists can be difficult, as a person may receive a regular paycheck pursuant to a contract, and insurance, and be subject to a clear chain of command, yet the State may characterize the relationship as “volunteerism”. See, for example, Decree No. 2020-0115, above note 35.

45 Articles on State Responsibility, above note 31, pp. 42, 47, and Art. 7.

46 Ibid., p. 46.

47 Alexis P. Kontos, “Private Security Guards: Privatized Force and State Responsibility under International Human Rights Law”, Non-State Actors and International Law, Vol. 199, No. 4, 2004, p. 213.

48 For example, the endorsement and support given by the Borno State governor to the CJTF: Eromosele Ebhomele, “Boko Haram: Civilian-JTF Gets Pay Rise from Borno Governor Zulum, Now to Earn N20,000”, Legit, 5 June 2019, available at: www.legit.ng/1241882-boko-haram-civilian-jtf-pay-rise-borno-governor-zulum-earn-n20000.html.

49 Articles on State Responsibility, above note 31, p. 46.

50 See also Hague Convention IV, Art. 3.

51 Sassòli, Marco, “State Responsibility for Violations of International Humanitarian Law”, International Review of the Red Cross, Vol. 84, No. 846, 2002, pp. 405–406Google Scholar. See also Longobardo, Marco, “The Relevance of the Concept of Due Diligence for International Humanitarian Law”, Wisconsin International Law Journal, Vol. 37, No. 1, 2019, p. 57Google Scholar; L. Cameron and V. Chetail, above note 38, pp. 161–164. Note that the Commentaries to the ASR consider Article 91 of Additional Protocol I to be the articulation of the general rule in ASR Article 7: see Articles on State Responsibility, above note 31, p. 46.

52 See, for example, the discussion above in relation to the mobilization of the CJTF in northeastern Nigeria and the Arrow Boys in South Sudan. This is consistent with global trends whereby the “vast majority” of conflicts are non-international: see Annyssa Bellal, The War Report: Armed Conflicts in 2018, Geneva Academy of International Humanitarian Law and Human Rights, 3 June 2019, available at: www.rulac.org/news/the-war-report-armed-conflicts-in-2018.

53 Articles on State Responsibility, above note 31, p. 43.

54 This is consistent with the examples provided in the ASR Commentaries, namely public corporations, semi-public entities, public agencies of various kinds, and private companies: Ibid., p. 43.

55 Ernest Ogbozor, “Understanding the Informal Security Sector in Nigeria”, ETH Zurich Centre for Security Studies, 4 October 2016, available at: https://tinyurl.com/btbtda2c. See also International Crisis Group, above note 5, p. 7, in relation to the regional decrees creating comités locaux de vigilance in Cameroon.

56 Articles on State Responsibility, above note 31, p. 43.

57 L. Cameron and V. Chetail, above note 38, p. 198. See also J. Maddocks, above note 3, pp. 62–77, and in particular her discussion of “quintessentially” government functions. For a discussion on the meaning given in the United States to tasks that are “inherently governmental” and may only be performed by members of the US Armed Forces or civilian employees of the Department of Defence, see Gillard, Emanuela-Chiara, “Business Goes to War: Private Military/Security Companies and International Humanitarian Law”, International Review of the Red Cross, Vol. 88, No. 863, 2006, pp. 550–551CrossRefGoogle Scholar.

58 Nieminen, Katja, “Rules of Attribution and the Private Military Contractors at Abu Ghraib: Private Acts or Public Wrongs?”, Finnish Year Book of International Law, Vol. 289, No. 15, 2004, p. 299Google Scholar. Note, however, that many countries provide for a “citizen's arrest” that does not involve the exercise of public authority, usually limited to stopping a person in the commission of a serious offence: see, for example, France, Criminal Procedure Code, Art. 73; Indonesia, Criminal Procedure Code, Art. 18(2). See also Articles on State Responsibility, above note 31, p. 43.

59 Articles on State Responsibility, above note 31, p. 43.

60 K. Nieminen, above note 58, p. 300.

61 Note that the Iran–US Tribunal considered that express authorization of the exercise of government authority was not required for the establishment of State responsibility, but instead considered that the exercise of government authority by the “Komitehs” or “Guards” created a reserve presumption whereby “the Respondent has the burden of coming forward with evidence showing that members of the ‘Komitehs’ or ‘guards’ were in fact not acting on its behalf, or were not exercising elements of government authority, or that it could not control them”. Iran–United States Claims Tribunal, Kenneth P. Yeager v. The Islamic Republic of Iran, Judgment, 1987, paras 43–45. This case is discussed further below in relation to Article 9 of the ASR.

62 L. Cameron and V. Chetail, above note 38, p. 168.

63 Moya, Vanessa Ballesteros, “The Privatization of the Use of Force Meets the Law of State Responsibility”, American University International Law Review, Vol. 30, No. 4, 2015, pp. 800–801Google Scholar.

64 Articles on State Responsibility, above note 31, p. 43. The ICRC's Customary Law Study also refers to responsibility for persons or entities “which [States] have empowered, under their internal law”: Jean-Marie Henckaerts and Louise Doswald-Beck (eds), Customary International Humanitarian Law, Vol. 1: Rules, Cambridge University Press, Cambridge, 2005 (ICRC Customary Law Study), Rule 149, available at: https://ihl-databases.icrc.org/customary-ihl/eng/docs/v1. See also L. Cameron and V. Chetail, above note 38, pp. 168–169.

65 Swiss Federal Department of Foreign Affairs, “Participating States of the Montreux Document”, available at: www.eda.admin.ch/eda/en/fdfa/foreign-policy/international-law/international-humanitarian-law/private-military-security-companies/participating-states.html.

66 Montreux Document, above note 11, Part 1, para. 7.

67 Ibid., Part 1, para. 7. See also E.-C. Gillard, above note 57, pp. 554–555. However, see also Cameron and Chetail's discussion of decisions by both the Iran–US Tribunal and the ICJ in which neither body required a finding that group was empowered by the domestic legal order in finding the State responsible: L. Cameron and V. Chetail, above note 38, pp. 169–170.

68 See the discussion of the Anambra State Vigilante Services per Law No. 9, Anambra State Vigilante Services Law, 2000, in Human Rights Watch, above note 40.

69 Articles on State Responsibility, above note 31, Arts 5, 7.

70 The ICJ considered Article 8 as reflecting customary law: ICJ, Bosnian Genocide, above note 31, para. 398. For a critique of this finding, see Cassese, Antonio, “The Nicaragua and Tadić Tests Revisited in Light of the ICJ Judgment on Genocide in Bosnia”, European Journal of International Law, Vol. 18, No. 4, 2007, p. 651CrossRefGoogle Scholar.

71 ICJ, Nicaragua, above note 36, para. 115 (emphasis added).

72 ICTY, Prosecutor v. Tadić, Case No. IT-94-1, Judgment (Appeals Chamber), 2 October 1995, para. 131 (emphasis added).

73 ICC, The Prosecutor v. Thomas Lubanga Dyilo, Case No. ICC-01/04-01/06-2842, Judgment (Trial Chamber), 5 April 2012, para. 541; ICC, The Prosecutor v. Jean-Pierre Bemba Gombo, Judgment (Trial Chamber III), 21 March 2016, para. 130. See also ICRC, Commentary on the First Geneva Convention: Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, 2nd ed., Geneva, 2016 (ICRC Commentary on GC I), paras 271–273.

74 ICJ, Bosnian Genocide, above note 31, paras 404–407.

75 Alternative tests for attribution have been applied by other international and regional decision-makers. The European Court of Human Rights (ECtHR), for example, considered that acts of the Turkish Republic of Northern Cyprus could be attributed to Turkey on the basis of “effective overall control”: ECtHR, Loizidou v. Turkey, Appl. No. 15318/89, 18 December 1996, para. 49; and see discussion in C. Kress, above note 2, pp. 107–109, 127–128; M. Milanovic, above note 2, pp. 345–346. The World Trade Organisation Appellate Body applies a test of “sufficient involvement” to determine whether acts of private entities may be considered “governmental”: see Alberto Alvarez-Jimenez, “International State Responsibility for Acts of Non-State Actors: The Recent Standards Set by the International Court of Justice in Genocide and Why the WTO Appellate Body Should Not Embrace Them”, Syracuse Journal of International Law and Commerce, Vol. 35, No 1, 2007, pp. 15–18. See also the discussion in Kristen E. Boon, “Are Control Tests Fit for the Future? The Slippage Problem in Attribution Doctrines”, Melbourne Journal of International Law, Vol. 15, No. 2, 2014, pp. 349–351, with regard to the applicability of control tests in relation to attributing acts of terrorism. In relation to the merits of the effective and overall control tests, the present author does not take a position on which test is to be preferred and refers readers to the differing views taken on this topic in M. Milanovic, above note 2, pp. 317–324; A. Cassese, above note 70; ICRC Commentary on GC I, above note 73, Art. 2, paras 268–271; M. Milanovic, “State Responsibility for Genocide”, European Journal of International Law, Vol. 17, No. 3, 2006, pp. 585–588; M. Sassòli, above note 51, p. 408.

76 ICTY, Tadić, above note 72, paras. 130–131. See also A. Cassese, above note 70, pp. 659–661.

77 See ICTY, Boškoski, above note 24, paras 194–206, for a description of the indicators that a group is an organized armed group.

78 C. Koos, above note 14, p. 1047. See also C. Dufka, above note 23, p. 28.

79 C. Koos, above note 14, p. 1048. See also the description of the Titweng and Gelweng in ICRC, above note 20, p. 57.

80 ICTY, Tadić, above note 72, para. 137.

81 Ibid., para. 151; ICTY, Prosecutor v. Aleksovski, Case No. IT-95-14/1, Judgment (Appeals Chamber), 24 March 2000, paras 138–145.

82 Examples of the ICTY's findings on overall control include ICTY, Prosecutor v. Rajić, Case No. IT-95-12, Review of the Indictment Pursuant to Rule 61 of the Rules of Procedure and Evidence (Trial Chamber), 13 September 1996, paras 13, 26, 32; ICTY, Prosecutor v. Blaškić, Case No. IT-95-14, Judgment (Trial Chamber), 3 March 2000, paras 83–123; ICTY, Tadić, above note 72, para. 156; ICTY, Prosecutor v. Kordić and Čerkez, Case No. IT-95-14/2, Judgment (Trial Chamber), 26 February 2001, para. 145; ICTY, Prosecutor v. Mucić et al., Case No. IT-96-21, Judgment (Appeals Chamber), 20 February 2001, paras 46–47; ICTY, Prosecutor v. Naletilić and Martinović, Case No. IT-98-34, Judgment (Trial Chamber), 31 March 2003, paras 198–201.

83 ICTY, Tadić, above note 72, para. 156.

84 Ibid., para 137; ICRC, Commentary on the First Geneva Convention, 2016, Article 2, para. 273.

85 ICTY, Tadić, above note 72, paras 121–122. For a critique of this aspect of the Tadić decision, see C. Kress, above note 2, pp. 128–129, 135–136; M. Milanovic, above note 2, pp. 319–320.

86 Articles on State Responsibility, above note 31, p. 47. In practice this may be difficult to determine in the absence of express instructions. See discussion in Oona A. Hathaway, Emily Chertoff, Lara Dominguez, Zachary Manfredi and Peter Tzeng, “Ensuring Responsibility: Common Article 1 and State Responsibility for Non-State Actors”, Texas Law Review, Vol. 95, No. 3, 2017, p. 552; K. Nieminen, above note 58, pp. 307–308; K. E. Boon, above note 75, p. 338.

87 C. A. M. Kwaja, above note 12, pp. 64–65.

88 Articles on State Responsibility, above note 31, p. 47.

89 O. A. Hathaway et al., above note 86, pp. 552–553. Kress, on the other hand, notes that Article 7 does not address de facto organs and highlights an absence of international practice extending it thus: C. Kress, above note 2, pp. 135–136.

90 Articles on State Responsibility, above note 31, p. 48. See also the discussion by Cameron and Chetail, who suggest that “the incidental character of the unlawful act regarding the particular mission can be determined by weighing whether or not the unlawful act was done to assist in the accomplishment of the mission, which can then help to answer the question of whether the instructing state had accepted the likelihood of its occurrence”: L. Cameron and V. Chetail, above note 38, pp. 207–208.

91 Articles on State Responsibility, above note 31, p. 49.

92 See, for example, C. Dufka, above note 23, p. 26, in relation to activities of the Dozo in Mali; D. E. Agbiboa, above note 7, pp. 14–16, in relation to the CJTF in Nigeria.

93 See, for example, C. Dufka, above note 23, pp. 15, 18, 19, in relation to Dogon and Bambara self-defence groups in Mali; C. A. M. Kwaja, above note 12, p. 28.

94 Articles on State Responsibility, above note 31, p. 49. For a discussion on the meaning of levée en masse, see ICRC, Commentary on the Third Geneva Convention: Convention (III) relative to the Treatment of Prisoners of War, 2nd ed., Geneva, 2020, Art. 4, paras 1064–1068.

95 Helmut Phillip Aust, “Complicity in Violations of International Humanitarian Law”, in Heike Krieger (ed.), Inducing Compliance with International Humanitarian Law: Lessons from the African Great Lakes Region, Cambridge University Press, Cambridge, 2015, p. 463.

96 Iran–United States Claims Tribunal, Yeager, above note 61, para. 104 (emphasis added).

97 C. Kress, above note 2, pp. 130–131. The ECtHR's jurisprudence on “connivance” and “acquiescence” is discussed below in relation to aiding and abetting.

98 In the discussion of “aiding and abetting” that follows, we see overlaps between “primary” and “secondary” rules. See M. Milanovic, above note 2, pp. 229–301, for a discussion on the history and utility of these labels; and Bernhard Graefrath, “Complicity in the Law of International Responsibility”, Belgian Review of International Law, Vol. 29, No. 2, 1996, pp. 372–373, specifically in relation to aiding and abetting.

99 Articles on State Responsibility, above note 31, p. 66.

100 The text of Article 16 does not refer to intent, but the Commentaries are explicit in their inclusion of this requirement, which has also been adopted by the ICJ in the Bosnian Genocide case, above note 31, para. 431. See also H. P. Aust, above note 95, pp. 451–452; Erika de Wet, “Complicity in Violations of Human Rights and Humanitarian Law by Incumbent Governments through Direct Military Assistance on Request”, International and Comparative Law Quarterly, Vol. 67, No. 2, 2019, p. 301. Jackson and Moynihan, on the other hand, reject that “intent” is required under Article 16: see Miles Jackson, Complicity in International Law, Oxford University Press, Oxford, 2015, pp. 159–161; Harriet Moynihan, Aiding and Assisting: Challenges in Armed Conflict and Counterterrorism, Chatham House, Royal Institute of International Affairs, London, 2016, p. 20.

101 H. P. Aust, above note 95, pp. 449–450. See also B. Graefrath, above note 98, p. 374; E. de Wet, above note 100, pp. 299–301.

102 Articles on State Responsibility, above note 31, p. 67.

103 In relation to the scope of Article 16 and the non-inclusion of non-State actors, see Richard Mackenzie-Gray Scott, “State Responsibility for Complicity in the Internationally Wrongful Acts of Non-State Armed Groups”, Journal of Conflict and Security Law, Vol. 24, No. 2, 2019.

104 ICJ, Bosnian Genocide, above note 31, paras 420, 423.

105 Human Rights Committee, Alzery v. Sweden, Communication No. 1416/2005, UN Doc. CCPR/C/88/D/1416/2005, Merits, 25 October 2006, para. 11.6.

106 ECtHR, Ilaşcu and Others and Romania (Intervening) v. Moldova and Russian Federation, Appl. No. 48787/99, Admissibility, Merits and Just Satisfaction, 8 July 2004, para. 318. See also ECtHR, El-Masri v. Former Yugoslav Republic of Macedonia, Appl. No. 39630/09, Merits and Just Satisfaction, 13 December 2012, para. 211; ECtHR, Al Nashiri v. Poland, Appl. No. 28761/11, Merits and Just Satisfaction, 24 July 2014, para. 517; ECtHR, Husayn (Abu Zubaydah) v. Poland, Appl. No. 7511/13, Merits and Just Satisfaction, 24 July 2014, paras 512–513; and discussion in Stephen Allen, “The Scope of Third-Party Responsibility for Serious Human Rights Abuses under the European Convention on Human Rights: Wrongdoing in the British Indian Ocean Territory”, Human Rights Law Review, Vol. 16, No. 4, 2016, p. 778–779; Nina H. B. Jørgensen, “Complicity in Torture in a Time of Terror: Interpreting the European Court of Human Rights Extraordinary Rendition Cases”, Chinese Journal of International Law, Vol. 16, No. 1, 2017, pp. 31–34.

107 However, see Berenice Boutin, “Responsibility in Connection with the Conduct of Military Partners”, Military Law and Law of War Review, Vol. 56, No. 1, 2017–18, pp. 68–69. Boutin contends that the prohibition on aiding and abetting human rights violation is lex specialis and is triggered by the lower threshold of “actual or constructive knowledge”. The obligation to protect against and prevent human rights violations is discussed separately below.

108 B. Graefrath, above note 98, pp. 375–376; H. P. Aust, above note 95, p. 452.

109 See also ICRC Customary Law Study, above note 64, Rule 144.

110 See, for example, ICJ, Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, 2004, ICJ Reports 136, para. 158; ICJ, Nicaragua, above note 36, para. 220; ICRC Commentary on GC I, above note 73, Art. 1, para. 145. See also Theo Boutruche and Marco Sassòli, “Expert Opinion on Third States’ Obligations vis-à-vis IHL Violations under International Law, with a Special Focus on Common Article 1”, 8 November 2016, p. 21; Knut Dörmann and Jose Serralvo, “Common Article 1 to the Geneva Conventions and the Obligation to Prevent International Humanitarian Law Violations”, International Review of the Red Cross, Vol. 96, No. 895–896, 2014, pp. 727, 734; Catherine Drummond, “Ensuring Respect for IHL by, and in Relation to the Conduct of, Private Actors”, in Eve Massinghaum and Annabel McConnachie (eds), Ensuring Respect for International Humanitarian Law, Routledge, London, 2020, pp. 66–67; Tom Ruys, “Of Arms, Funding and Non-Lethal Assistance: Issues Surrounding Third-State Intervention in the Syrian Civil War”, Chinese Journal of International Law, Vol. 13, No. 1, 2014, p. 26. See, by contrast, Riccardo Pisillo Mazzeschi, who considers that in the few areas of international law where due diligence obligations could be considered to exist, there is no corresponding obligation to abstain: Riccardo Pisillo Mazzeschi, “The Due Diligence Rule and the Nature of the International Responsibility of States”, German Yearbook of International Law, Vol. 35, 1992, p. 43.

111 ICJ, Nicaragua, above note 36, para. 220; ICRC Commentary on GC I, above note 73, Art. 1, para. 158.

112 Ibid., para. 184.

113 Ibid., para. 159. See also H. P. Aust, above note 95, pp. 457–458. This is not uniformly accepted – see, for example, the discussion in T. Ruys, above note 110, pp. 27–28.

114 The obligation on States to prevent unlawful detention of persons by non-State entities is discussed below.

115 E. de Wet, above note 100, pp. 302–303, gives examples of knowledge triggers for States supporting other States.

116 Articles on State Responsibility, above note 31, Art. 4.

117 ICRC Commentary on GC I, above note 73, Art. 50, paras 2929–2930; ICRC Customary Law Study, above note 64, Rule 158, “ii. Perpetrators”.

118 See the above section entitled “Overall Control of the Group” for a discussion on community defence groups as organized armed groups. See also C. Drummond, above note 110, p. 65.

119 See also African Commission on Human and Peoples’ Rights (ACHPR), Zimbabwe Human Rights NGO Forum v. Zimbabwe, Communication No. 245/02, 39th Ordinary Session, 11–15 May 2006, para. 143; and the ECtHR's invocation of the obligation on States to “secure to everyone within their jurisdiction the rights and freedoms” defined in the ECHR as underpinning the obligation to prevent violations, in ECtHR, El-Masri, above note 106, para. 198.

120 Human Rights Committee, General Comment No. 31, “The Nature of the General Legal Obligation Imposed on States Parties to the Covenant”, UN Doc. CCPR/C/21/Rev.1/Add.13, 29 March 2004, para. 8. See also Monica Hakimi, “State Bystander Responsibility”, European Journal of International Law, Vol. 21, No. 2, 2010, p. 351.

121 Human Rights Committee, General Comment No. 36, “Article 6: Right to Life”, UN Doc. CCPR/C/GC/36, 3 September 2019, para. 21. See also Inter-American Court of Human Rights (IACtHR), Velásquez Rodriguez v. Honduras, 29 July 1988, para. 174; ECtHR, Osman v. United Kingdom, Case No. 23452/94, Merits, 28 October 1998, para. 116. By contrast, see ICJ, Corfu Channel (United Kingdom v. Albania), Merits, Judgment, 1949, ICJ Reports 1949, pp. 22–23, where the ICJ considered responsibility for the failure to act (omission) to be triggered by Albania's knowledge of the laying of landmines. See, further, Articles on State Responsibility, above note 31, p. 35; ICJ, Case Concerning Pulp Mills on the River Uruguay (Argentina v. Uruguay), Merits, Judgment, 2010, ICJ Reports 2010, para. 101.

122 ICJ, Nicaragua, above note 36, p. 114.

123 ICRC Commentary on GC I, above note 73, Art. 1, para. 167. See also K. Dörmann and J. Serralvo, above note 110, pp. 727–730. Other more specific due diligence obligations exist in IHL, for example in relation to situations of occupation under Article 43; the wounded, sick and shipwrecked in international armed conflicts; and prisoners of war: see L. Cameron and V. Chetail, above note 38, pp. 236–243. Not all accept that common Article 1 carries with it positive obligations. See, for example, Egan, Brian, “International Law, Legal Diplomacy, and the Counter-ISIL Campaign: Some Observations”, International Law Studies, Vol. 92, No. 1, 2016, p. 245Google Scholar; but also Oona A. Hathaway and Zachary Manfrei, “The State Department Adviser Signals a Middle Road on Common Article 1”, Just Security, 12 April 2016, available at: www.justsecurity.org/30560/state-department-adviser-signals-middle-road-common-article-1/.

124 ICRC Commentary on GC I, above note 73, Art. 1, para. 172. See also V. Ballesteros Moya, above note 63, pp. 831–832; M. Longobardo, above note 51, p. 59; L. Cameron and V. Chetail, above note 38, p. 245; B. Boutin, above note 107, p. 273; K. Dörmann and J. Serralvo, above note 110, 708–709.

125 ICRC Commentary on GC I, above note 31, Art. 1, para. 186. Akin to the test applied in the Bosnian Genocide case, above note 31, para. 431.

126 But see the discussion above in relation to the ECtHR's view of responsibility on the basis of “acquiescence or connivance”.

127 M. Hakimi, above note 120, p. 354.

128 ECtHR, Osman v. United Kingdom, Case No. 23452/94, Merits, 28 October 1998, para. 116; Human Rights Committee, above note 121, para. 21; Committee Against Torture, General Comment No. 2, “Implementation of Article 2”, UN Doc. CAT/C/GC/2, 24 January 2008, para. 18; IACtHR, Velásquez Rodriguez, above note 121, para. 175.

129 ICRC Commentary on GC I, above note 73, Art. 1, para. 187. See also M. Longobardo, above note 51, p. 62; K. Dörmann and J. Serralvo, above note 110, pp. 724–725.

130 ICRC Commentary on GC I, above note 73, Art. 1, para. 214; O. A. Hathaway et al., above note 86, pp. 585–589.

131 Human Rights Committee, General Comment No. 35, “Article 9: Liberty and Security of Person”, UN Doc. CCPR/C/GC/35, 26 December 2014, para. 7. See also ACHPR, Commission Nationale des Droits de l'Homme et des Libertes v. Chad, Communication No. 74/92, Finding, 1995, para. 22; and discussion in Tilman Rodenhäuser, Organising Rebellion: Non-State Armed Groups under International Humanitarian Law, Human Rights Law and International Criminal Law, Oxford University Press, Oxford, 2018, pp. 139–143. See also A. I. L. Campbell, “Positive Obligations under the ECHR: Deprivation of Liberty by Private Actors”, Edinburgh Law Review, Vol. 10, No. 3, 2006, pp. 149–151. discussing the ECtHR's decision in Storck v. Germany wherein the Court considered the lack of State control as key to Germany's non-fulfilment of its obligations to prevent the deprivation of liberty by non-State actors as well as the right to private life.

132 See O. A. Hathaway et al., above note 86, pp. 585–587; Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, 1465 UNTS 85, 1984, Art. 10. For an example of a regulatory framework provided for community defence groups in Burkina Faso, see Decree No. 2020-0115, above note 35. Note that the training requirement for such “volunteers” is only two weeks.

133 Human Rights Committee, above note 121, para. 21.

134 Ibid., para. 15. In relation to best practice regarding training, see O. A. Hathaway et al., above note 86, pp. 586–587. See Brian Finucane, “Partners and Legal Pitfalls”, International Law Studies, Vol. 92, 2016, p. 426, in relation to the risks associated with partners that engage in the conduct of hostilities, including the absence of effective commanders or leaders able to exercise effective command and control over their members.

135 B. Boutin, above note 107, p. 74.

136 Human Rights Committee, above note 121, para. 21. See also Human Rights Committee, above note 120, para. 8; Inter-American Court of Human Rights, Velásquez Rodriguez v Honduras, 29 July 1988, para 176; ACHPR, above note 131, para. 22.

137 Human Rights Committee, above note 121, para. 27.

138 ICRC Customary Law Study, above note 64, Rule 158.

139 Human Rights Committee, above note 121, para. 28; ECtHR, Finogenov and Others v. Russia, Appl. Nos 18299/03, 27311/03, Judgment, 20 December 2011, paras 270–272; ECtHR, El-Masri, above note 106, paras 186–189; ICRC and Geneva Academy, Guidelines on Investigating Violations of International Humanitarian Law: Law, Policy and Good Practice, Geneva, 2019, para. 32.

140 ICRC and Geneva Academy, above note 139, para. 34. See also the discussion in T. Rodenhäuser, above note 131, p. 198.

141 L. Harriman, I. Drewy and D. Deng, above note 17, p. 13; D. E. Agbiboa, above note 7, pp. 18–19.