1 Articles on Responsibility of States for Internationally Wrongful Acts, UN Doc. A/56/10, 43, UN Doc. A/RES/56/83 (2001), Annex, UN Doc. A/CN.4/L.602/Rev 1, GAOR 56th Session Supp 10, 43, Commentary, para. 1 (see also paras. 2 and 3).

2 Other studies have done this already. See, e.g., A. Gourgourinis, ‘General/Particular International Law and Primary/Secondary Rules: Unitary Terminology of a Fragmented System’, (2011) 22 European Journal of International Law 993; U. Linderfalk, ‘State Responsibility and the Primary-Secondary Rules Terminology – The Role of Language for an Understanding of the International Legal System’, (2009) 78 Nordic Journal of International Law 53.

3 P. Alston, ‘The “Not-a-Cat” Syndrome: Can the International Human Rights Regime Accommodate Non-State Actors?’, in P. Alston (ed.), Non-State Actors and Human Rights (2005) 3, at 4 and 19.

4 See S. Sivakumaran, ‘Beyond States and Non-State Actors: The Role of State-Empowered Entities in the Making and Shaping of International Law’, (2017) 55 Columbia Journal of Transnational Law 343.

5 ‘Mode’ in this sense purely refers to the manner in which a concept operates and is dealt with in a particular field, in this instance, state responsibility within international law.

6 ARSIWA, Art. 2, Commentary, para. 3.

7 See supra note 1.

8 See Section 3.1 (below).

9 F. V. Garcia-Amador, First Report, International Responsibility, A/CN.4/96, YBILC (1956), vol. II.

10 Ibid., at 187.

11 Ibid.

12 Ibid.; see also ibid., at 208.

13 Ibid., at 209.

14 Second Report, International Responsibility, F. V. Garcia Amador, A/CN.4/106, YBILC (1957), vol. II, at 104.

15 Ibid., at 106.

16 Ibid.

17 Ibid.; see also F. V. Garcia-Amador, Third Report, International Responsibility, A/CN.4/111, YBILC (1958), vol. II, at 54.

18 F. V. Garcia-Amador, Fifth Report, International Responsibility, A/CN.4/125 and Corr. 1, YBILC (1960), vol. II, at 63.

19 For a summary of why this occurred see D. Müller, ‘The Work of Garcia Amador on State Responsibility for Injuries Caused to Aliens’, in J. Crawford, A. Pellet and S. Olleson (eds.), The Law of International Responsibility (2010), at 69.

20 Fourth Report, State responsibility, Roberto Ago, A/CN.4/264 and Add.1, YBILC (1972), vol. II, at 118.

21 Ibid.

22 Ibid.

23 Ibid., at 131–8.

24 Ibid., at 133, 137.

25 Ibid., at 135–6. See, e.g., ‘The British Foreign Office also sent to its consular officers abroad the following instruction, which was transmitted to the United States Ambassador in Mexico City by the British Minister in 1913: “Where claims are made for compensation for damages done by insurgents in armed insurrections against a government which was unable to control them, claimants should be reminded that His Majesty’s Government do not regard a government as liable in such cases unless that government were negligent and might have prevented the damage arising”’ (emphasis added).

26 R. Ago, Seventh Report, State Responsibility, A/CN.4/307 and Add. 1 & 2 and Corr. 1 & 2, YBILC (1978), vol. I(1), at 37.

27 Ibid., at 32–7.

28 Ibid., at 32.

29 Ibid., at 36.

30 ILC Report, thirtieth session, 8 May–28 July 1978, UNGA, Thirty-third session, Supp. No. 10, A/33/10, YBILC (1978), vol. II(2), at 81; Draft articles on State responsibility: Text adopted by the Drafting Committee: Articles 23–7 and title of Ch. IV of the draft – reproduced in A/CN.4/SR.1513 and SR.1524, A/CN.4/L.271 and Add.1, YBILC (1978), vol. I, at 206.

31 R. Ago, Eighth Report, State Responsibility, A/CN.4/318 and Add.1 to 4, YBILC (1979), vol. II(1), at 63–4.

32 W. Riphagen, Seventh report, State responsibility, (A/CN.4/397 and Corr.1 & 2 and Add.1 & Corr.1), YBILC (1986), vol. II(1), at 8.

33 G. Arangio-Ruiz, Second report, State responsibility, A/CN.4/425 & Corr.1 and Add.1 & Corr.1, YBILC (1989), vol. II(1), at 6, 15, 16, 26, 27.

34 ILC Report, forty-eighth session, 6 May–26 July 1996, UNGA, Fifty-first session, Supp. No.10, A/51/10, YBILC (1996), vol. II(2), at 60.

35 Observations and comments of Governments on chapters I, II and III of Part I of the draft articles on State responsibility for internationally wrongful acts, A/CN.4/328 and Add.1-4, YBILC (1980), vol. II(1), at 92, 93, 100, 101, 103; Comments of Governments on part one of the draft articles on State responsibility for internationally wrongful acts, A/CN.4/342 and Add.1-4, YBILC (1981), vol. II(1), at 75.

36 Comments and observations received from Governments, A/CN.4/488 and Add. 1–3 (1998), at 123.

37 Ibid., at 126.

38 Ibid.

39 James Crawford inferred that the UK and Germany took a similar position. See J. Crawford, Second report, State responsibility, A/CN.4/498 and Add.1–4 (1999), at 27.

40 Ibid., at 28.

41 Ibid.

42 See note 36 and preceding text.

43 See Crawford, supra note 39, at 28.

44 Ibid., at 28–9.

45 Ibid., at 29 (emphasis added).

46 Ibid.

47 ILC Report, fifty-first session, 3 May–23 July 1999, UNGA, Fifty-fourth session, Supp. No.10, A/54/10, YBILC (1999), vol. II(2), at 50; State responsibility: Titles and texts of draft articles adopted by the Drafting Committee: articles 16 to 26 bis (chapter III), 27 to 28 bis (chapter IV) and 29 to 35 (chapter V) – reproduced in document A/CN.4/SR.2605, para.4, A/CN.4/L.574 [and Corr.1 and 3], YBILC (1999), vol. I, at 275.

48 See ARSIWA, Art. 14 and Commentary, in particular para. 14.

49 See analysis in Section 3.1 (below) and also J. Vidmar, ‘Some Observations on Wrongfulness, Responsibility and Defences in International Law’, (2016) 63 Netherlands International Law Review 335, at 349.

50 Ibid. Vidmar, at 350.

51 It is often undertaken with the aim of enhancing the ‘original’ output and is a commonly used methodology in a number of fields in addition to international law. See R. Kurzweil, ‘The accelerating power of technology’, TED Talks, February 2005, available at www.ted.com/talks/ray_kurzweil_on_how_technology_will_transform_us.

52 S. Sivakumaran, ‘Techniques in International Law-Making: Extrapolation, Analogy, Form and the Emergence of an International Law of Disaster Relief’, (2017) 28 European Journal of International Law 1097, at 1108–16.

53 Ibid., at 1112. For example, in creating the Draft Articles on the Expulsion of Aliens, the ILC combined ‘aspects of traditional customary international law, human rights lat [sic], refugee law’ and extrapolated ‘current trends’ to ‘restate’ the law in this area (Harvard Human Rights Journal, Forum on the International Law Commission’s ‘Draft Articles on the Expulsion of Aliens’, Introduction, available at www.harvardhrj.com/forum-essays/).

54 C. Engel, ‘General and Specific Rules’, (2005) 161 Journal of Institutional and Theoretical Economics 350; J. D. Dana, Jr. ‘General and Specific Legal Rules: A Mechanism Design Approach’, (2005) 161 Journal of Institutional and Theoretical Economics 347.

55 See Sivakumaran, supra note 52, at 1112.

56 ARSIWA, Art. 6, Commentary, paras. 2–7.

57 ARSIWA, Art. 7, Commentary, paras. 4–6.

58 ARSIWA, Art. 8, Commentary.

59 ARSIWA, Art. 9, Commentary, para. 2.

60 ARSIWA, Art. 21 and Commentary.

61 See Sivakumaran, supra note 52, at 1114.

62 See J. Crawford, State Responsibility: The General Part (2013), 390.

63 See Section 2 (above).

64 It is unclear from where the ILC got the distinction. The terminology might have been adopted from Hart, who made this distinction in the context of domestic law: H. L. A. Hart, The Concept of Law (1961). However, it should be noted that ‘the ILC’s distinction between primary and secondary norms may prima facie appear, to a large extent, to be influenced by H. L. A. Hart’s Concept of Law; nevertheless, Hartian thought should not be considered as the origin of the distinction (A. Gourgourinis, ‘General/Particular International Law and Primary/Secondary Rules: Unitary Terminology of a Fragmented System’, (2011) 22 European Journal of International Law 993, at 1016).

65 See analysis in Sections 2 (above) and 3.2.2 (below).

66 R. Yotova, ‘The Principles of Due Diligence and Prevention in International Environmental Law’, (2016) 75 Cambridge Law Journal 445.

67 A. Boivin, ‘Complicity and beyond: International law and the transfer of small arms and light weapons’, (2005) 87 International Review of the Red Cross 467, at 479, 489–90; R. P. Barnidge Jr, ‘The Due Diligence Principle Under International Law’, (2006) 8 International Community Law Review 81, at 92, 120.

68 See case law of the Inter-American Court of Human Rights (IACtHR) and European Court of Human Rights (ECtHR) (below).

69 Y. Levashova, ‘Fair and Equitable Treatment and Investor’s Due Diligence Under International Investment Law’, (2020) 67 Netherlands International Law Review 233; E. De Brabandere, ‘Host States’ Due Diligence Obligations in International Investment Law’, (2015) 42 Syracuse Journal of International Law and Commerce 319.

70 M. N. Schmitt and S. Watts, ‘Beyond State-Centrism: International Law and Non-state Actors in Cyberspace’, (2016) 21 Journal of Conflict & Security Law 595, at 602–7.

71 T. Becker, Terrorism and the State: Rethinking the Rules on State Responsibility (2006), 119–30 (reviewing practice on this issue); R. B. Lillich and J. M. Paxman, ‘State Responsibility for Injuries to Aliens Occasioned by Terrorist Activities’, (1977) 26 American University Law Review 217, at 251–76.

72 Goekce v. Austria, UN Doc. CEDAW/C/39/D/5/2005 (2007), at paras. 12.1.2–12.1.4; Opuz v. Turkey, App. no. 33401/02, (ECtHR, 9 June 2009), at paras. 165, 200; L. Hasselbacher, ‘State Obligations Regarding Domestic Violence: The European Court of Human Rights, Due Diligence, And International Legal Minimums of Protection’, (2010) 8 Northwestern Journal of Human Rights 190.

73 UNGA Res. A/RES/21/2222, Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, Art. 6 (emphasis added).

74 K. Tinkler, ‘Rogue Satellites Launched into Outer Space: Legal and Policy Implications’, Just Security, 7 June 2018, available at www.justsecurity.org/57496/rogue-satellites-launched-outer-space-legal-policy-implications/.

75 Alabama claims of the United States of America against Great Britain (United States v. Great Britain), Award of 14 September 1872, RIAA, vol. XXIX (1872), at 125–34.

76 Ibid., at 127.

77 R. Bernhardt (ed.), Max Planck Encyclopedia of Public International Law (1987), vol. X, at 139.

78 Ibid.

79 Ibid.

80 See Alabama claims, supra note 75, at 129.

81 Ibid., at 130.

82 D. Davitti, ‘On the Meanings of International Investment Law and International Human Rights Law: The Alternative Narrative of Due Diligence’, (2012) 12 Human Rights Law Review 421, at 445.

83 R. Barnidge Jr, The Due Diligence Principle Under International Law (2006), at 98–9.

84 Thomas H. Youmans (U.S.A.) v. United Mexican States, UNRIAA (1926), vol. IV, at 110, para 11.

85 Massey v. United Mexican States, UNRIAA (1927), vol. IV, at 155, para. 159.

86 United States Diplomatic and Consular Staff in Tehran (United States of America v. Iran), Judgment, 24 May 1980, (1980) ICJ Rep., at 3.

87 Ibid., para. 63.

88 Ibid.

89 Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Judgment of 27 June 1986, [1986] ICJ Rep. 14, paras. 157–60.

90 Ibid., para. 157

91 See Section 4 (below) for further analysis on this matter.

92 Ibid.

93 However, this flexibility is limited. See E. Askin, ‘Due Diligence Obligation in Times of Crisis: A Reflection by the Example of International Arms Transfers’, EJIL: Talk!, 1 March 2017, available at www.ejiltalk.org/due-diligence-obligation-in-times-of-crisis-a-reflection-by-the-example-of-international-arms-transfers/; A. V. Freeman, Responsibility of States for Unlawful Acts of their Armed Forces (1955), at 277–8.

94 Case Concerning Pulp Mills on the River Uruguay (Argentina v. Uruguay), Judgment of 20 April 2010, [2010] ICJ Rep. 14.

95 Ibid., para. 101.

96 This stance takes insights from the work of the ILC in its Draft Articles on Prevention of Transboundary Harm from Hazardous Activities (2001), UN Doc. A/RES/56/82 (2001), 56 UN GAOR Supp (No. 49) at 498, Supp. (No. 10) A/56/10 (V.E.1). It should be noted that these provisions apply ‘to activities not prohibited by international law’ (see Art. 1, Commentary, paras. 1–17) and thus concern international liability, which is a separate issue from international responsibility for conduct that is prohibited by international law; see N. L. J. T. Horbach, ‘The Confusion About State Responsibility and International Liability’, (1991) 4 Leiden Journal of International Law 47.

97 See Pulp Mills, supra note 94, para. 205.

98 Velasquez Rodriguez v. Honduras, (Ser. C) No. 4 (IACtHR, 29 July 1988), para. 166.

99 Ibid., para. 182.

100 Ibid.

101 Ibid., para. 79.

102 Ibid., para. 172.

103 Ibid., paras. 180, 167 respectively.

104 See, for example, Caso 19 Comerciantes, (Ser. C) No. 109 (IACtHR, 5 July 2004), paras. 29, 30, 112, 140, 203; ‘Mapiripán Massacre’, (Ser. C) No. 122 (IACtHR, 15 September 2005), paras. 226, 246, 304; Pueblo Bello Massacre, (Ser. C) No. 140 (IACtHR, 31 January 2006), paras. 126, 139, 140, 151, 170, 201; Masacres de Ituango, (Ser. C) No. 148 (IACtHR, 1 July 2006), paras. 134, 291, 310, 315, 316, 317, 328, 330, 399, 402, 417; Masacre de La Rochela, (Ser. C) No. 163 (IACtHR, 11 May 2007), paras. 2, 111, 149, 150, 155-164, 165, 172, 194, 199, 202, 203, 209, 288, 293,-297.

105 Velasquez Rodriguez, supra note 98, paras. 166, 174, 176, 180, 188.

106 See, for example, Lopes De Sousa Fernandes v. Portugal, App. no. 56080/13 (ECtHR, 19 December 2017), paras. 31, 47, 49, 64; Ilaşcu and Others v. Moldova and Russia, App. no. 48787/99 (ECtHR, 8 July 2004), paras. 322–52; Tahsin Acar v. Turkey, App. no. 26307/95 (ECtHR, 8 April 2004); Slivenko v. Latvia, App. no. 48321/99 (ECtHR, 9 October 2003); Kudła v. Poland, App. no. 30210/96 (ECtHR, 26 October 2000), paras. 109, 129; Osman v. United Kingdom, App. no. 87/1997/871/1083 (ECtHR, 28 October 1998), para. 116.

107 Ibid. Lopes De Sousa Fernandes, para. 31.

108 N. White, ‘Due Diligence Obligations of Conduct: Developing a Responsibility Regime for PMSCs’, (2012) 31 Criminal Justice Ethics 233.

109 T. Christakis, ‘Challenging the “Unwilling or Unable” Test’, in A. Peters and C. Marxsen (eds.), Self-Defence Against Non-State Actors: Impulses from the Max Planck Trialogues on the Law of Peace and War (MPIL Research Paper Series No. 2017-07), at 18; see also P-M. Dupuy, ‘Reviewing the Difficulties of Codification: On Ago’s Classification of Obligations of Means and Obligations of Result in Relation to State Responsibility’, (1999) 10 European Journal of International Law 371, at 376–8; J. Crawford, ‘Revising the Draft Articles on State Responsibility’, (1999) 10 European Journal of International Law 435, at 440–2.

110 See Garcia-Amador, supra note 9, at 190; see also Section 4 (below).

111 N. McDonald, ‘The Role of Due Diligence in International Law’, (2019) 68 International & Comparative Law Quarterly 1041.

112 There can sometimes be conflation between ‘general principles of law’ and ‘principles of international law’. See analysis on this issue in C. Voigt, ‘The Role of General Principles in International Law and their Relationship to Treaty Law’, (2008) 31 Nordic Journal of Law & Justice 3, at 5–9; see also M. C. Bassiouni, ‘A Functional Approach to “General Principles of International Law’, (1990) 11 Michigan Journal of International Law 768.

113 Statute of the ICJ, 59 Stat. 1055 (1945) TS 993, Art. 38(1)(c); see also A. Pellet, ‘Article 38’, in A. Zimmermann et al. (eds.), The Statute of the International Court of Justice: A Commentary (2012), at 731.

114 W. Friedmann, ‘The Uses of “General Principles” in the Development of International Law’, (1963) 57 American Journal of International Law 279; A. McNair, ‘The General Principles of Law Recognized by Civilized Nations’, (1957) 33 British Yearbook of International Law 1.

115 Corfu Channel Case (United Kingdom v. Albania), Judgement, 9 April 1949, [1949] ICJ Rep., 4, at para. 22 (emphasis added).

116 J. Ellis, ‘General Principles and Comparative Law’, (2011) 22 European Journal of International Law 949.

117 R. Versteeg, ‘Perspectives on Foreseeability in the Law of Contracts and Torts: The Relationship Between “Intervening Causes” and “Impossibility”’, (2011) 5 Michigan State Law Review 1497; J. Bonnitcha and R. McCorquodale, ‘The Concept of “Due Diligence” in the UN Guiding Principles on Business and Human Rights’, (2017) 28 European Journal of International Law 899, at 902–3.

118 Hadley v. Baxendale [1854] EWHC J70; Blyth v Birmingham Waterworks Co [1856] 11 Ex Ch 781; Palsgraf v. Long Island Railroad (NY, 1928) 162 NE 99; Smith v. Littlewoods [1987] UKHL 18; Fairchild v. Glenhaven Funeral Services Ltd [2002] UKHL 22; D v. East Berkshire Community Health NHS Trust [2005] 2 WLR 993.

119 See Dupuy, supra note 109, at 375.

120 See notes 107–9 and preceding text.

121 M. N. Schmitt, ‘In Defense of Due Diligence in Cyberspace’, (2015) 125 Yale Law Journal 68, at 73.

122 See ARSIWA, Art. 55, Commentary, paras. 1–6.

123 See Corfu Channel Case, supra note 115, at 22.

124 J. A. Hessbruegge, ‘The Historical Development of the Doctrines of Attribution and Due Diligence in International Law’, (2004) 36 Journal of International Law & Politics 265, at 275.

125 Trail smelter case (United States v. Canada), UNRIAA (1941), vol. III, at 1905.

126 Ibid., at 1963; see also C. Eagleton, The Responsibility of States in International Law (1928), at 80.

127 United States v. Hasan and ors, Decision on motion to dismiss (29 October 2010), No 2:10 cr56 [ED VA], at para. 72.

128 R (on the application of Gentle and another), [2008] UKHL 20.

129 Ibid., at para. 59.

130 See supra note 118.

131 In addition to the practice already analysed above (see notes 91 and 118 and preceding text), see Section 4.1 (below); see-also-Federal Securities Act (1933) US; see Bonnitcha and McCorquodale, supra note 117, at 906.

132 For some further examples, although there are more, see C. Bright at al., ‘Options for Mandatory Human Rights Due Diligence in Belgium’, Leuven Centre for Global Governance Studies (2020); R. McCorquodale et al., ‘Human Rights Due Diligence in Law and Practice: Good Practices and Challenges for Business Enterprises’, (2017) 2 Business and Human Rights Journal 195; T. Baudesson et al., ‘New French law imposing due diligence requirements in relation to human rights, health and safety, and the environment’, Briefing Note (Clifford Chance, 3 March 2017); N. Ahiauzu and T. Inko-Tariah, ‘Applicability of anti-money laundering laws to legal practitioners in Nigeria: NBA v. FGN & CBN’, (2016) 19 Journal of Money Laundering Control 329; M. Conway, ‘A New Duty of Care? Tort Liability from Voluntary Human Rights Due Diligence in Global Supply Chains’, (2015) 40 Queen’s Law Journal 741; Decree n. 8.420 (2015), Art. 42, XIII (Brazil).

133 C. Eggett, ‘The Role of Principles and General Principles in the “Constitutional Processes” of International Law’, (2019) 66 Netherlands International Law Review 197.

134 T. Koivurova, ‘Due Diligence’, in R. Wolfrum (ed.), Max Planck Encyclopedia of Public International Law (2010).

135 McDonald, The Role of Due Diligence in International Law (2019), at 1044–9, 1054.

136 There is an issue concerning what is actually positive international law within the state responsibility framework that is believed by many ostensible positivists to be legal doctrine. The act of pretending (knowingly or unknowingly) that a concept is part of positive international law versus it genuinely existing as such raises many questions about international law-making and reality, which are beyond the scope of this article. See H. J. Morgenthau, ‘Positivism, Functionalism, and International Law’, (1940) 34 American Journal of International Law 260.

137 For example, consider how the ARSIWA are presumed to reflect customary international law. See F. L. Bordin, ‘Reflections of Customary International Law: The Authority of Codification Conventions and the ILC Draft Articles in International Law’, (2014) 63 International & Comparative Law Quarterly 535; D. D. Caron, ‘The ILC Articles on State Responsibility: The Paradoxical Relationship between Form and Authority’, (2002) 96 American Journal of International Law 857.

138 North Sea Continental Shelf (Germany/Denmark; Germany/Netherlands), Judgment, 20 February 1969, ICJ Rep. [1969], 3, para. 77; Statute of the ICJ, 59 Stat. 1055 (1945) TS 993, Art. 38(1)(b).

139 Related to the points raised in notes 136 and 137, the ‘invisible college of international lawyers’ has arguably created the contemporary international law of state responsibility, not states. International courts/tribunals in relying on the ARSIWA have claimed that certain provisions reflect international custom. Well-known scholars, usually based in North America or Western Europe, then adopt these rulings to assert that those same provisions are customary rules. This process occurs independently of whether state practice and opinio juris exists to substantiate such assertions. Furthermore, the UN General Assembly resolution (56/83) that included the ARSIWA was passed without a vote and states that the General Assembly ‘takes note of’ the ARSIWA, which is not an expression for adopting its content as such. State silence is not a robust argument for claiming that customary international law exists. See UNGA Res. 56/83, UN Doc. A/RES/56/83 (12 December 2001); O. Schachter, ‘The Invisible College of International Lawyers’, (1977) 72 Northwestern University Law Review 217; K. T. Gaubatz and M. MacArthur, ‘How International Is “International” Law?’, (2001) 22 Michigan Journal of International Law 239; R. D. Sloane, ‘On the Use and Abuse of Necessity in the Law of State Responsibility’, (2012) 106 American Journal of International Law 447; S. Talmon, ‘Determining Customary International Law: The ICJ’s Methodology between Induction, Deduction and Assertion’, (2015) 26 European Journal of International Law 417.

140 Several problems arise when the matter of customary international law is raised. See M. Hakimi, ‘Making Sense of Customary International Law’, (2020) 118 Michigan Law Review 1487.

141 See Section 3.1 (above).

142 See Sivakumaran, supra note 52, at 1116.

143 Ibid.

144 Ibid.

145 Ibid., at 1115.

146 Ibid.

147 Ibid.

148 Ibid., at 1126; see also W. Kälin, ‘The Guiding Principles on Internal Displacement – Introduction’, (1998) 10 International Journal of Refugee Law 557, at 561–2.

149 See V. Held, ‘Morality, care, and international law’, (2011) 4 Ethics & Global Politics 173, at 176–8, 185–8; T. M. Franck, ‘Non-Treaty Law-Making: When, Where and How?’, in R. Wolfrum and V. Roeben (eds.), Developments of International Law in Treaty Making (2005), 417, in particular at 425.

150 This understanding corresponds with rulings like that of the ICJ in Corfu Channel, which also expounded a generalized formulation of due diligence.

151 F. Green, ‘Fragmentation in Two Dimensions: The ICJ’s Flawed Approach to Non-State Actors and International Legal Personality’, (2008) 9 Melbourne Journal of International Law 47.

152 See Koivurova, supra note 134; R. Pisillo-Mazzeschi, ‘The Due Diligence Rule and the Nature of the International Responsibility of States’, (1992) 35 German Yearbook of International Law 9.

153 J. Kulesza, Due Diligence in International Law (2016), 1.

154 This assessment would not be solely after the fact, as part of it would depend on what knowledge a state had at the relevant time when the wrongful conduct of the non-state actor occurred.

155 The potential for this problem was noticed recently after the ILC finalised its work. See V. Lowe, ‘Responsibility for the Conduct of Other States’, (2002) 101 Japanese Journal of International Law & Diplomacy 1, at 2.

156 In light of such realities, international law could use more imaginative solutions to the problems it faces: A. Bianchi, ‘Imagination’s Place in International Law’, Graduate Institute of International and Development Studies, 17 April 2019, available at www.graduateinstitute.ch/communications/news/imaginations-place-international-law.

157 See, for example, the developing complicity rule in general international law that encompasses non-state actors: R. Mackenzie-Gray Scott, ‘State Responsibility for Complicity in the Internationally Wrongful Acts of Non-State Armed Groups’, (2019) 24 Journal of Conflict & Security Law 373; see also the developing general rule of state instigation in international law: M. Jackson, ‘State Instigation in International Law: A General Principle Transposed’, (2019) 30 European Journal of International Law 391.

158 See analysis in notes 136–40 and preceding text.

159 These criticisms are particularly prevalent with respect to the ARSIWA provisions on attribution, in which a number of arguments have been advanced in attempts to contend that new attribution rules should be created. See, for example, L. Chircop, ‘A Due Diligence Standard of Attribution in Cyberspace’, (2018) 67 International & Comparative Law Quarterly 643; V. Lanovoy, ‘The Use of Force by Non-State Actors and the Limits of Attribution of Conduct’, (2017) 28 European Journal of International Law 563; V. Lanovoy, ‘The Use of Force by Non-State Actors and the Limits of Attribution of Conduct: A Rejoinder to Ilias Plakokefalos’, (2017) 28 European Journal of International Law 595; V. Lanovoy, Complicity and its Limits in the Law of International Responsibility (2016), 306–29; D. Amoroso, ‘Moving towards Complicity as a Criterion of Attribution of Private Conducts: Imputation to States of Corporate Abuses in the US Case Law’, (2011) 24 Leiden Journal of International Law 989, at 991–4.

160 M. Hakimi, ‘State Bystander Responsibility’, (2010) 21 European Journal of International Law 341, at 349.

161 Ibid., at 354.

162 See Mackenzie-Gray Scott, supra note 157, at 384–406.

163 Within international criminal law an analogous framework exists through the doctrine of superior responsibility. See S. Sivakumaran, ‘Command Responsibility in Irregular Groups’, (2012) 10 Journal of International Criminal Justice 1129, in particular at 1130–7; I. Bantekas, ‘The Contemporary Law of Superior Responsibility’, (1999) 93 American Journal of International Law 573.

164 See Askin, supra note 93

165 This point is also emphasized in N. McDonald, ‘The Role of Due Diligence in International Law’, (2019) 68 International and Comparative Law Quarterly, at 1054.

166 A. Peters, ‘The refinement of international law: From fragmentation to regime interaction and politicization’, (2017) 15 International Journal of Constitutional Law 671; G. Hafner, ‘Pros and Cons Ensuing from Fragmentation of International Law’, (2004) 25 Michigan Journal of International Law 849.

167 R. Garciandia, ‘State responsibility and positive obligations in the European Court of Human Rights: The contribution of the ICJ in advancing towards more judicial integration’, (2020) 33 Leiden Journal of International Law 177.

168 R. P. Barnidge Jr, ‘States’ Due Diligence Obligations with Regard to International Non-State Terrorist Organisations Post-11 September 2001: The Heavy Burden that States Must Bear’, (2005) 16 Irish Studies in International Affairs 103.

169 To the extent that human rights treaty bodies have considered claims for such differentiation, they have not been willing to accept it: see, for example, Human Rights Committee, Concluding Observations: Algeria, UN Doc. CCPR/C/79/Add.95 (1998), at para. 3 (‘a general climate of violence heighten the responsibilities of the State party to re-establish and maintain the conditions necessary for the enjoyment and protection of fundamental rights’); Human Rights Committee, Concluding Observations: Tanzania (1992), para. 5; see also L. Rajamani, Differential Treatment in International Environmental Law (2006), 20.

170 The consequences of such a practice could create harmonized ‘best practices’, which could even become binding on states under customary international law through their own state practice and opinio juris. In this sense, a binding framework of standard-setting within the law of state responsibility for non-state actors could emerge.

171 See Bonnitcha and McCorquodale, supra note 117, at 902.

172 See Hakimi, supra note 160, at 344.

173 See analysis in Section 4 (below).

174 Communication No. 17/2008 (29 July 2011), UN Doc. CEDAW/C/49/D/17/2008; Communication No. 1020/2001 (19 September 2003), UN Doc. CCPR/79/D/1020/2001.

175 See analysis in Section 3.2 (above).

176 ILA Study Group on Due Diligence in International Law, First Report (7 March 2014), at 26.

177 This includes the findings present in the preparatory work of the ARSIWA.

178 See Prosecutor v. Stanislav Galic (Judgement and Opinion), Case No. IT-98-29-T (5 December 2003), at para. 58.

179 See supra note 20, at 134, 138.

180 R. (on the application of Smith) and Equality and Human Rights Commission (intervening) v. Secretary of State for Defence [2010] UKSC 29, para. 84.

181 See Hakimi, supra note 160, at 371.

182 See, for example, the Modern Slavery Act 2015.

183 G. Cronogue, ‘Rebels, Negligent Support, and State Accountability: Holding States Accountable for the Human Rights Violations of Non-State Actors’, (2013) 23 Duke Journal of Comparative & International Law 365.

184 This would also depend on the norm and (probably) the non-state actor in question.

185 See, for example, Da Penha v. Brazil, Case 12.051, IACHR, Report No. 54/01 (2000), para. 56; Opuz v. Turkey, App. no 33401/02 (ECtHR, 9 June 2009), paras. 91–106, 132; Saadi v. Italy, App. no. 37201/06 (ECtHR, 28 February 2008); Ilaşcu and Others v. Moldova and Russia, App. no. 48787/99 (ECtHR, 8 July 2004), paras. 28–185, 380–2, 393–4. However, see also Committee on the Elimination of Discrimination Against Women, Communication No. 6/2005: Yildirim v. Austria, UN Doc. CEDAW/C/39/D/6/2005 (2007), para. 12.1.2 (Austria held responsible without consideration of scale).

186 Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field. Geneva, 12 August 1949, Commentary (2016), paras. 118, 153.

187 Ibid., para. 135.

188 Ibid., paras. 150, 165.

189 This becomes particularly important if the company’s conduct cannot be attributed to the state, for example, under Arts. 5, 8 or 11 (ARSIWA).

190 M. Turcan and N. Ozpinar, ‘“Who let the dogs out?”: A critique of the security for hire option in weak states’, (2009) 2 Dynamics of Asymmetric Conflict 143.

191 J. W. Nickel, ‘How Human Rights Generate Duties to Protect and Provide’, (1993) 15 Human Rights Quarterly 77, at 81. This understanding brings with it a normative dimension about what a due diligence secondary rule should do.

192 See Nicaragua, supra note 89, para. 220; Armed Activities on the Territory of the Congo (Democratic Republic of the Congo v. Uganda), Judgment of 19 December 2005, [2005] ICJ Rep., at 168, paras. 211, 345; Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, 9 July 2004, [2004] ICJ Rep., at 136, paras. 158–9; UNSC Res. 681 (20 December 1990), UN Doc. S/RES/681, para. 5.

193 Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro), Judgment of 26 February 2007, [2007] ICJ Rep., at 43.

194 Ibid., para. 430.

195 Ibid.

196 Ibid.

197 Ibid.

198 Matters of proximity/remoteness are also linked to attribution considerations, especially with respect to the interpretations of ‘effective control’ expounded by the Dutch courts (see infra note 201).

199 T. Christakis, Challenging the “Unwilling or Unable” Test (2017), 18.

200 F. V. Garcia-Amador, Second Report, International Responsibility, A/CN.4/106, YBILC (1957), vol. II, at 122.

201 See Hasan Nuhanovic v. the Netherlands, Court of Appeal in The Hague, Civil Law Section (5 July 2011), LJN: BR5388; 200.020.174/01; Mustafic et. al. v. the Netherlands, Court of Appeal in The Hague, Civil Law Section (5 July 2011), LJN: BR5386; 200.020.173/01; Hasan Nuhanovic v. the Netherlands, District Court in The Hague, Civil Law Section (10 September 2008), LJN: BF0181; 265615/HA ZA 06-1671; Mustafic et. al. v. the Netherlands, District Court in The Hague, Civil Law Section (10 September 2008), LJN: BF0182; 265618/HA ZA 06-1672; Mothers of Srebrenica v. The Netherlands, Judgment (16 July 2014), The Hague District Court, Case No. C/09/295247.

202 See analysis on the link with attribution in Section 5.2 (below).

203 Arts. 5 and 7.

204 There can be a tendency to conflate due diligence with attribution because of the shortcomings in the latter group of tests. See Chircop, supra note 159; Velasquez Rodriguez, supra note 98, para. 172.

205 Justinian, The Digest of Roman Law: Theft, Rapine, Damage and Insult (1979), at 91.

206 Ibid.

207 ILA Study Group on Due Diligence in International Law, First Report (7 March 2014), at 26.

208 Ibid., Second Report (July 2016), at 13.

209 Draft Articles on Prevention of Transboundary Harm from Hazardous Activities (2001), Art. 3, Commentary, para. 10; see also paras. 5, 18.

210 See also, for example, the principle of ‘non-refoulement’: J. Pirjola, ‘Shadows in Paradise – Exploring Non-Refoulement as an Open Concept’, (2008) 19 International Journal of Refugee Law 639.

211 Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field. Geneva, 12 August 1949, Commentary (2016), para. 150.

212 ICRC, Customary IHL Database, Rule 14, available at ihl-databases.icrc.org/customary-ihl/eng/docs/v1_rul_rule14

213 ICRC, Customary IHL Database, Rule 15, available at ihl-databases.icrc.org/customary-ihl/eng/docs/v1_rul_rule15

214 I. Robinson and E. Nohle, ‘Proportionality and precautions in attack: The reverberating effects of using explosive weapons in populated areas’, (2016) 98 International Review of the Red Cross 107.

215 Ibid.

216 Donoghue v. Stevenson [1932] UKHL 100.

217 J. C. Smith and P. Burns, ‘Donoghue v. Stevenson: The Not So Golden Anniversary’, (1983) 46 Modern Law Review 147; R. F. V. Heuston, ‘Donoghue v. Stevenson in Retrospect’, (1957) 20 Modern Law Review 1.

218 L. Green, ‘Foreseeability in Negligence Law’, (1961) 61 Columbia Law Review 1401, at 1413.

219 Responsibilities and obligations of States sponsoring persons and entities with respect to activities in the Area, Advisory Opinion, No. 17, 1 February 2011, ITLOS rep. [2011] at 10, para. 131.

220 See Hakimi, supra note 160, at 380.

221 Restatement (Third), Foreign Relations Law of the United States (1987), s. 711 n. 2B; F. V. García-Amador, L. B. Sohn and R. R. Baxter, Recent Codification of the Law of State Responsibility for Injuries to Aliens (1974), at 27; Committee on the Elimination of Discrimination against Women, Communication No. 5/2005: Goekce v. Austria, UN Doc. CEDAW/C/39/D/5/2005 (2007), para. 12.1.4; Osman v. United Kingdom, para. 116.

222 F. V. Garcia Amador, Sixth Report, International Responsibility, A/CN.4/134 and Add.1, YBILC (1961), vol. II, at 41.

223 H. Moynihan, ‘Aiding and Assisting: The Mental Element Under Article 16 of the International Law Commission’s Articles on State Responsibility’, (2018) 67 International & Comparative Law Quarterly 455, at 464.

224 Prosecutor v. Jean-Pierre Bemba Gombo, Pre-Trial Chamber, Judgement, ICC-01/05-01/08, 15 June 2009, para. 363.

225 See Lowe, supra note 155, at 8.

226 Soering v. United Kingdom, App. no. 14038/88 (ECtHR, 7 July 1989), paras. 88, 91, 92, 98, 111.

227 See I. Plakokefalos, ‘Causation in the Law of State Responsibility and the Problem of Overdetermination: In Search of Clarity’, (2015) 26 European Journal of International Law 471.

228 Such an outcome, however, may not be beneficial or desirable depending on the context. See C. R. Sunstein, Laws of Fear: Beyond the Precautionary Principle (2012).

229 See Garcia-Amador, supra note 17, at 54.

230 A. Nollkaemper, ‘The ECtHR Finds Macedonia Responsible in Connection with Torture by the CIA, but on What Basis?’, EJIL: Talk!, 24 December 2012, available at www.ejiltalk.org/the-ecthr-finds-macedonia-responsible-in-connection-with-torture-by-the-cia-but-on-what-basis/.

231 See also the point made in the second paragraph of Section 3.3 (above).

232 A. Seibert-Fohr, ‘From Complicity to Due Diligence: When Do States Incur Responsibility for Their Involvement in Serious International Wrongdoing?’, (2017) 60 German Yearbook of International Law 667.

233 See Mackenzie-Gray Scott, supra note 157, at 386–7.

234 Ibid., at 393–4.

235 It might be argued that so long as state responsibility is established then it does not matter whether such responsibility is direct or indirect. However, such arguments would fail to consider the factors that come into play after state responsibility for non-state actor conduct has been established. Whether state responsibility is direct or indirect affects the legal consequences relating to how the wronged party can lawfully respond. Consider, for example, the type of countermeasures that could be utilized, which must be proportional, or the reparations that the responsible state would be under an obligation to make. See T. M. Franck, ‘On Proportionality of Countermeasures in International Law’, (2008) 102 American Journal of International Law 715; D. Shelton, ‘Righting Wrongs: Reparations in the Articles on State Responsibility’, (2002) 96 American Journal of International Law 833; ARSIWA, Art. 31, Commentary, paras. 1–14; E. Cannizzaro, ‘The Role of Proportionality in the Law of International Countermeasures’, (2001) 12 European Journal of International Law 889. See also note 258 and preceding text.

236 See Mackenzie-Gray Scott, supra note 157, at 402–6.

237 Case Concerning Application of the International Convention on the Elimination of All Forms of Racial Discrimination (Georgia v. Russia), Judgment, 1 April 2011, [2011] ICJ Rep., at 70.

238 Ibid., Order for Provisional Measures, 15 October 2008, [2008] ICJ Rep., at 353, paras. 109–11.

239 Ibid., para. 13.

240 Ibid., para. 149(4).

241 Where the language of ‘support’ is used, state involvement will likely be more akin to complicity.

242 See supra note 237, para. 77.

243 Ibid., para. 187(2).

244 Ibid., para. 165.

245 See Mackenzie-Gray Scott, supra note 157, at 386–7.

246 Ibid.

247 H. P. Aust, ‘The UN Human Rights Due Diligence Policy: An Effective Mechanism against Complicity of Peacekeeping Forces?’, (2015) 20 Journal of Conflict & Security Law 61.

248 M. García-Salmones Rovira, ‘The Politics of Interest in International Law’, (2014) 25 European Journal of International Law 765; D. Sloss, ‘Do International Norms Influence State Behavior?’, (2006) 38 George Washington International Law Review 159; E. A. Posner, ‘Do States Have a Moral Obligation to Obey International Law?’, (2003) 55 Stanford Law Review 1901.

249 See Mackenzie-Gray Scott, supra note 157 at 396–8.

250 Ibid.

251 Ibid.

252 For more on why complicity by omission is problematic and unhelpful see Mackenzie-Gray Scott, supra note 157, at 386–7.

253 Ibid., at 387–9.

254 It should be noted that if viewed from the perspective of primary rules, a due diligence breach is conventionally construed as direct responsibility for a state’s own failings with respect to preventing, suppressing or addressing the wrong of a non-state actor, and not for the non-state actor’s conduct itself. See analysis in Section 5.2 (below).

255 See Garcia-Amador, supra note 18, at 60–6.

256 Ibid., at 63.

257 Janes et al. (USA) v. United Mexican States, UNRIAA (1925), vol. IV, at 82–98.

258 F.V. Garcia-Amador, Sixth Report, International Responsibility, A/CN.4/134 and Add.1, YBILC (1961), vol. II, at 34.

259 Ibid., at 63.

260 Ibid.

261 V. P. Tzevelekos, ‘Reconstructing the Effective Control Criterion in Extraterritorial Human Rights Breaches: Direct Attribution of Wrongfulness, Due Diligence, and Concurrent Responsibility’, (2014) 36 Michigan Journal of International Law 129, at 133.

262 See Garcia-Amador, supra note 258, at 63.

263 See Chircop, supra note 159.

264 Ibid., at 645 and 653 respectively.

265 See notes 201 and 204 and preceding text.

266 See analysis in notes 136–140 and preceding text. See also W. D. Coplin, ‘International Law and Assumptions about the State System’, (1965) 17 World Politics 615.

267 See also the arguments in the second and third paragraphs of Section 3.3 (above).

268 See Garcia-Amador, supra note 200, at 122.