1 This article focuses on situations of international armed conflict and the law applicable to that type of armed conflict. While the concept of “combatants” is limited to international armed conflicts, the principle of distinction is applicable to all types of armed conflict. Much of the analysis in this article can thus be applied mutatis mutandis to situations qualifying as non-international armed conflict as well, but exploring the specific nuances of that context falls outside of its scope.

2 See Meddings, David R., “Civilians and War: A Review and Historical Overview of the Involvement of Non-Combatant Populations in Conflict Situations”, Medicine, Conflict and Survival, Vol. 17, No. 1, 2001CrossRefGoogle Scholar.

3 International Committee of the Red Cross (ICRC), International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, Geneva, 2007, p. 15. One historical exception is the levée en masse – i.e., the spontaneous uprising of the civilian population against the invading forces of the enemy. As documented in a recent study, this concept originated during the revolutionary wars in America and France, but there have been virtually no instances of levée en masse in modern armed conflicts: see Crawford, Emily, “Tracing the Historical and Legal Development of the Levée en Masse in the Law of Armed Conflict”, Journal of the History of International Law, Vol. 19, No. 3, 2017CrossRefGoogle Scholar.

4 Wenger, Andreas and Mason, Simon J. A., “The Civilianization of Armed Conflict: Trends and Implications”, International Review of the Red Cross, Vol. 90, No. 872, 2008, p. 848CrossRefGoogle Scholar.

5 See e.g. Helmi Noman, “The Emergence of Open and Organized Pro-Government Cyber Attacks in the Middle East: The Case of the Syrian Electronic Army”, OpenNet Initiative, May 2011, available at: https://opennet.net/emergence-open-and-organized-pro-government-cyber-attacks-middle-east-case-syrian-electronic-army (all internet references were accessed in April 2023); Stefan Soesanto, The IT Army of Ukraine: Structure, Tasking, and Ecosystem, Center for Security Studies, ETH Zürich, June 2022.

6 See e.g. Drew Harwell, “Instead of Consumer Software, Ukraine's Tech Workers Build Apps of War”, Washington Post, 24 March 2022, available at: www.washingtonpost.com/technology/2022/03/24/ukraine-war-apps-russian-invasion/; Dan Sabbagh, “Ukrainians Use Phone App to Spot Deadly Russian Drone Attacks”, The Observer, 29 October 2022, available at: www.theguardian.com/world/2022/oct/29/ukraine-phone-app-russia-drone-attacks-eppo.

7 See, further, Jonathan Horowitz, “One Click from Conflict: Some Legal Considerations Related to Technology Companies Providing Digital Services in Situations of Armed Conflict”, forthcoming.

8 For a legal perspective on the supposedly blurred line between combatants and non-combatants in cyberspace, see Mačák, Kubo, “Unblurring the Lines: Military Cyber Operations and International Law”, Journal of Cyber Policy, Vol. 6, No. 3, 2021, pp. 419–421CrossRefGoogle Scholar, available at: www.tandfonline.com/doi/full/10.1080/23738871.2021.2014919.

9 Russia, “Statement by Dr. Vladimir Shin, Deputy Director of the Department of International Information Security of the Ministry of Foreign Affairs of the Russian Federation, at the Online Consultations of the Open-Ended Working Group on the Developments in the Field of Information and Telecommunications in the Context of International Security”, 30 September 2020, p. 2.

10 Japan, “Basic Position of the Government of Japan on International Law Applicable to Cyber Operations”, 28 May 2021, p. 7.

11 Brazil, “National Contribution on the Subject of How International Law Applies to the Use of Information and Communications Technologies by States”, in Official Compendium of Voluntary National Contributions on the Subject of How International Law Applies to the Use of Information and Communications Technologies by States Submitted by Participating Governmental Experts in the Group of Governmental Experts on Advancing Responsible State Behaviour in Cyberspace in the Context of International Security Established Pursuant to General Assembly Resolution 73/266, UN Doc. A/76/136, 13 July 2021, p. 23.

12 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 6, available at: https://ihl-databases.icrc.org/customary-ihl/eng/docs/v1. See also Supreme Court of Israel, The Public Committee against Torture in Israel and Others v. Government of Israel and Others, HCJ 769/02, Judgment, 14 December 2006, para. 38.

13 Yves Sandoz, Christophe Swinarski and Bruno Zimmerman (eds), Commentary on the Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949, ICRC, Geneva, 1987 (ICRC Commentary on the APs), p. 619, para. 1945.

14 ICRC Customary Law Study, above note 12, p. 23.

15 Nils Melzer, Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law, ICRC, Geneva, 2009 (ICRC Interpretive Guidance), p. 46.

16 International Criminal Court (ICC), The Prosecutor v. Callixte Mbarushimana, Decision on the Confirmation of Charges, 16 December 2011, para. 148.

17 Some are nonetheless very similar in their approaches: see e.g. Norway, Manual i krigens folkerett, 2013 (Norwegian Military Manual), paras 3.24–3.27 (relying on the criteria of (1) “damage or injury”, (2) “direct cause” and (3) “intent”). Military manuals of other States, several of which were drafted before the ICRC Interpretive Guidance, either do not examine the meaning of direct participation in hostilities or employ differently formulated legal tests: see e.g. Australia, Law of Armed Conflict, Australian Defence Force, Canberra, 2006, p. 5-10, para. 5.36; Canada, The Law of Armed Conflict at the Operational and Tactical Levels: Joint Doctrine Manual, Department of National Defence, Ottawa, 2001, p. 3-4, para. 28; New Zealand, Manual of Armed Forces Law, Vol. 4, New Zealand Defence Force, Wellington, 2019 (New Zealand Military Manual), pp. 6-15–6–17, paras 6.5.13–6.5.17; Spain, Orientaciones: El derecho de los conflictos armados [Guidelines on the Law of Armed Conflict], 2nd ed., Ministerio de Defensa, 2007, para. 5.2.a.(2)(a); Switzerland, Bases légales du comportement à l'engagement [Regulation on Legal Bases for Conduct during an Engagement], Swiss Army, 2005 (Swiss Military Manual), para. 197; United Kingdom, The Manual of the Law of Armed Conflict, Joint Service Publication 383, Ministry of Defence, 1 July 2004 (UK Military Manual), para. 5.3.3; United States, Department of Defense Law of War Manual, Office of General Counsel, Department of Defense (DoD), Washington, DC, June 2015 (updated December 2016) (DoD Military Manual), section 5.8.

18 Colombia, Manual de derecho operacional [Operational Law Manual], 2nd ed., Ministerio de Defensa Nacional, Comando General de las Fuerzas Militares, Santafé de Bogotá, 2015, p. 41.

19 Denmark, Military Manual on International Law Relevant to Danish Armed Forces in International Operations, Danish Ministry of Defence, Defence Command Denmark, 2016 (Danish Military Manual), pp. 168–169.

20 France, International Law Applied to Operations in Cyberspace, Ministry of the Armies, 2019 (French Position Paper), p. 13.

21 Germany, On the Application of International Law in Cyberspace: Position Paper, March 2021 (German Position Paper), p. 8.

22 Michael N. Schmitt and Liis Vihul (eds), Tallinn Manual 2.0 on International Law Applicable to Cyber Operations, Cambridge University Press, Cambridge, 2017 (Tallinn Manual 2.0), Rule 97, commentary para. 5.

23 Akande, Dapo, “Clearing the Fog of War? The ICRC's Interpretive Guidance on Direct Participation in Hostilities”, International and Comparative Law Quarterly, Vol. 59, 2010, p. 192CrossRefGoogle Scholar.

24 See International Criminal Tribunal for the former Yugoslavia (ICTY), Prosecutor v. Pavle Strugar, Case No. IT-01-42-A, Judgement (Appeals Chamber), 17 July 2008, para. 178; ICC, The Prosecutor v. Bahr Idriss Abu Garda, Case No. ICC-02/05-02/09, Decision on the Confirmation of Charges, 8 February 2010, para. 83.

25 Tallinn Manual 2.0, above note 22, Rule 97, commentary para. 5 (“actions that do not qualify as a cyber attack will satisfy this criterion so long as they negatively affect the enemy militarily”); but see United Kingdom, “Application of International Law To States’ Conduct In Cyberspace: UK Statement”, Foreign, Commonwealth and Development Office, 3 June 2021, para. 25, which seems to place the bar higher (i.e., at the level of attack).

26 For a recent overview of the debate, see e.g. Kubo Mačák and Laurent Gisel, “Grammar: Rules in a Cyber Conflict”, in Patryk Pawlak and François Delerue (eds), A Language of Power? Cyber Defence in the European Union, Chaillot Paper, EUISS, Paris, 2022, pp. 65–67. For an up-to-date overview of State positions on the matter, see “Attack (International Humanitarian Law)”, Cyber Law Toolkit, 30 March 2023, available at: https://cyberlaw.ccdcoe.org/wiki/Attack_(international_humanitarian_law).

27 ICRC Commentary on the APs, above note 13, pp. 618–619; see also Supreme Court of Israel, Public Committee against Torture, above note 12, para. 33.

28 ICRC Interpretive Guidance, above note 15, p. 48; see also Nils Melzer, Summary Report of the Third Expert Meeting on the Notion of Direct Participation in Hostilities, ICRC, Geneva, 23–25 October 2005 (2005 DPH Report), pp. 29 (wiretapping), 31 (clearing mines).

29 Tallinn Manual 2.0, above note 22, Rule 97, para. 5.

30 See e.g. Ryan Gallagher, “‘Cyber Partisans’ Say They Hacked Belarus Rail to Disrupt Russian Troops”, Bloomberg, 24 January 2022, available at: www.bloomberg.com/news/articles/2022-01-24/hackers-say-they-breached-belarusian-rail-to-stop-russian-troops.

31 ICRC Interpretive Guidance, above note 15, p. 50.

32 Nils Melzer, Summary Report of the Second Expert Meeting on the Notion of Direct Participation in Hostilities, ICRC, Geneva, 25–26 October 2004 (2004 DPH Report), p. 5.

33 ICRC Interpretive Guidance, above note 15, p. 48 fn. 103.

34 Ibid., p. 53.

35 But see Tallinn Manual 2.0, above note 22, Rule 97, para. 5, describing a minority position according to which “maintaining passive cyber defences of military cyber assets” also qualifies as direct participation in hostilities, because by enhancing one State's own military capacity, it necessarily weakens an adversary's relative position. In the view of the present author, this is an overbroad reading which is inconsistent with generally accepted interpretations of IHL in this context: for instance, it is generally accepted that civilians working in munitions factories in rear areas are not directly participating in hostilities even though this activity does enhance the military capacity of their State. See e.g. Michael Bothe, Karl Josef Partsch and Waldemar A. Solf, New Rules for Victims of Armed Conflicts: Commentary on the Two 1977 Protocols Additional to the Geneva Conventions of 1949, Martinus Nijhoff, The Hague, 1982, p. 344; ICRC Interpretive Guidance, above note 15, p. 53 fn. 123; DoD Military Manual, above note 17, para. 5.8.2.2 fn. 255.

36 See also Jonathan Horowitz, “Private Companies in Cyber Operations during Armed Conflict”, Articles of War, 13 January 2022, available at: https://lieber.westpoint.edu/private-companies-cyber-operations-armed-conflict/.

37 D. Akande, above note 23, p. 187.

38 ICRC Interpretive Guidance, above note 15, p. 53; but see e.g. Schmitt, Michael N., “The Interpretive Guidance on the Notion of Direct Participation in Hostilities: A Critical Analysis”, Harvard National Security Journal, Vol. 1, 2010, p. 30Google Scholar (“[t]he reference to ‘one causal step’ is unfortunate”); Wallace, David, Reeves, Shane and Powell, Trent, “Direct Participation in Hostilities in the Age of Cyber: Exploring the Fault Lines”, Harvard National Security Journal, Vol. 12, 2021, p. 194Google Scholar (arguing that “the ‘case-by-case’ or ‘contextual’ approach taken by the United States and others is arguably more operationally palatable as it provides the necessary flexibility for determining whether a particular cyber operation would amount to a direct participation in hostilities”).

39 See Tallinn Manual 2.0, above note 22, Rule 97, commentary para. 6, describing “conducting DDoS operations against enemy military external systems” as an “unambiguous example” of direct participation in hostilities.

40 ICRC Interpretive Guidance, above note 15, p. 55. See also 2005 DPH Report, above note 28, p. 35; D. Wallace, S. Reeves and T. Powell, above note 38, p. 180.

41 ICRC Interpretive Guidance, above note 15, pp. 54–55.

42 2004 DPH Report, above note 32, p. 5.

43 But see Tallinn Manual 2.0, above note 22, Rule 97, commentary para. 5, describing “gathering information on enemy operations by cyber means and passing it to one's own State's armed forces” as an “unambiguous example” of direct participation in hostilities. For reasons described in the main text, it is submitted that this is an overbroad interpretation of the relevant law.

44 Shane Darcy, To Serve the Enemy: Informers, Collaborators, and the Laws of Armed Conflict, Oxford University Press, Oxford, 2019, p. 113.

45 ICRC Interpretive Guidance, above note 15, p. 66.

46 Hague Rules of Air Warfare, 1923, Article 16, emphasis added. More recently, this interpretation has been embraced by the ICTY and the ICC: ICTY, The Prosecutor v. Pavle Strugar, Case No. IT-01-42-A, Judgement (Appeals Chamber), 17 July 2008, para. 177; ICC, The Prosecutor v. Bahr Idriss Abu Garda, Case No. ICC-02/05-02/09, Decision on the Confirmation of Charges, 8 February 2010, para. 81.

47 See ICRC Interpretive Guidance, above note 15, pp. 54–55. See also 2005 DPH Report, above note 28, p. 22 (“only intelligence gathering that had a direct connection to attack or defence should be regarded as part of the hostilities”); 2004 DPH Report, above note 32, p. 5 (“the provision of information with the intent to influence the hostilities should constitute DPH”).

48 French Position Paper, above note 20, p. 15 (“the penetration of a military system by a party to an armed conflict with a view to gathering tactical intelligence for the benefit of an adversary for the purposes of an attack constitutes direct participation in hostilities”) (emphasis added); German Position Paper, above note 21, p. 8 (“transmitting tactical targeting information for an attack … could suffice in order to consider a civilian person as directly participating in hostilities”) (emphasis added).

49 See also ICRC Commentary on the APs, above note 13, p. 901, para. 3187, noting that “gathering and transmission of military information” per se are examples of “indirect acts of participation” in hostilities (emphasis added).

50 I am grateful to Ramin Mahnad for suggesting these examples.

51 For an analysis of the object and purpose of these rules from the perspective of cyber operations during armed conflicts, see Mačák, Kubo, “Military Objectives 2.0: The Case for Interpreting Computer Data as Objects under International Humanitarian Law”, Israel Law Review, Vol. 48, No. 1, 2015, pp. 77–78CrossRefGoogle Scholar (with references), available at: https://tinyurl.com/2emrppjj.

52 See, similarly, Michael N. Schmitt, “Ukraine Symposium – Using Cellphones to Gather and Transmit Military Information, A Postscript”, Articles of War, 4 November 2022, section “Warning the Civilian Population”, available at: https://lieber.westpoint.edu/civilians-using-cellphones-gather-transmit-military-information-postscript/.

53 ICRC Interpretive Guidance, above note 15, p. 60. See also e.g. Byron Tau, “App Taps Unwitting Users Abroad to Gather Open-Source Intelligence”, Wall Street Journal, 24 June 2021, available at: www.wsj.com/articles/app-taps-unwitting-users-abroad-to-gather-open-source-intelligence-11624544026 (reporting on how innocuous data collected through apps can be used for military purposes).

54 ICRC Interpretive Guidance, above note 15, p. 60.

55 Ibid., p. 59 fn. 150.

56 Such as when a civilian is “totally unaware” of the fact that they are involved in the conduct of hostilities: see note 53 above and the associated text. See also J. Horowitz, above note 7, discussing the relevance of subjective considerations in the context of technological companies operating in armed conflict environments.

57 See e.g. Germany, Federal Prosecutor General at the Federal Court of Justice (Bundesgeneralanwalt beim Bundesgerichtshof), Investigation Proceedings against Colonel (Oberst) Klein and Company Sergeant Major (Hauptfeldwebel) Wilhelm Because of Suspected Offences under the International Crimes Code and Other Offences, Case No. 3 BJs 6/10-4, Decision to Terminate Proceedings Pursuant to Section 170 Para. 2 Sentence 1 of the Penal Procedure Code, 16 April 2010 (so-called Fuel Tankers case), p. 60: “Die unmittelbare Teilnahme an Feindseligkeiten im Sinne des Konfliktsvölkerrechts ist von der Willensrichtung des sich Beteiligenden unabhängig, denn der zeitweilige Verlust des Schutzes als Zivilist ist eine Folge davon, dass diese Person objektiv eine militärische Bedrohung darstellt.” (ICRC translation: “The direct participation in hostilities as understood under the international law of armed conflict is independent of the individual will of the person concerned because the temporary loss of protection as a civilian is the consequence of the person objectively constituting a military threat.”) However, some States incorporate the element of intent into their assessment of whether an act constitutes direct participation in hostilities: see e.g. Danish Military Manual, above note 19, p. 171; Norwegian Military Manual, above note 17, paras 3.24, 3.27.

58 Cf. Egloff, Florian J. and Cavelty, Myriam Dunn, “Attribution and Knowledge Creation Assemblages in Cybersecurity Politics”, Journal of Cybersecurity, Vol. 7, No. 1, 2021, p. 5CrossRefGoogle Scholar, explaining that the attacker's intent is an element of attribution that is frequently difficult to substantiate with robust data.

59 ICRC Interpretive Guidance, above note 15, p. 59.

60 See ibid., pp. 63–64, describing the decisive question as “whether the conduct of a civilian, in conjunction with the circumstances prevailing at the relevant time and place, can reasonably be perceived as an act designed to support one party to the conflict by directly causing the required threshold of harm to another party”.

61 See J. Horowitz, above note 7.

62 ICRC Interpretive Guidance, above note 15, pp. 75–76; see also e.g. New Zealand Military Manual, above note 17, p. 6-15, para. 6.5.11. But see Tallinn Manual 2.0, above note 22, Rule 97, commentary para. 13, noting that the “International Group of Experts was divided over the issue of whether a presumption against direct participation applies”; and D. Wallace, S. Reeves and T. Powell, above note 38, p. 196, asserting that it is “unclear” how this dilemma will be resolved in the future.

63 The use of force by individuals in defence of themselves or others should be distinguished from the use of force by States in self-defence against an armed attack, which is governed by the jus ad bellum and is beyond the scope of this article. See, similarly, ICRC Interpretive Guidance, above note 15, p. 61 fn. 158.

64 Ibid., p. 61. See also ICRC, Summary Report of the First Expert Seminar on Direct Participation in Hostilities under International Humanitarian Law, Geneva, September 2003 (2003 DPH Report), p. 6: “All the experts who spoke on the subject stressed that individual civilians using a proportionate amount of force in response to an unlawful and imminent attack against themselves or their property should not be considered as directly participating in hostilities.”

65 See, further, J. Horowitz, above note 7, arguing that it is in companies’ interest to explain their actions in order to mitigate risks.

66 See Protocol Additional (I) to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, 1125 UNTS 3, 8 June 1977 (entered into force 7 December 1978) (AP I), Art. 43(2).

67 Anthony Rogers, “Combatant Status”, in Elizabeth Wilmshurst and Susan Breau (eds), Perspectives on the ICRC Study on Customary International Humanitarian Law, Cambridge University Press, Cambridge, 2007, p. 122.

68 United States, “International Law – The Conduct of Armed Conflict and Air Operations”, Air Force Pamphlet 110-31, Department of the Air Force, 19 November 1976, p. 5-8. Air Force Pamphlet 110-31 infers this obligation from the general immunity from attack owed to civilians under IHL. Another historical example can be found in United Kingdom, The Law of War on Land, Being Part III of the Manual of Military Law, Her Majesty's Stationery Office, London, 1958, p. 626 (no longer in force). See also Swiss Military Manual, above note 17, para. 172: “Les personnes civiles ne peuvent pas participer aux hostilités.” (ICRC translation: “Civilians may not participate in hostilities.”)

69 ICRC, International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, Geneva, 2011, p. 44.

70 Declaration Respecting Maritime Law, Paris, 1856, Art. 1 (“Privateering is, and remains, abolished”).

71 ICRC Interpretive Guidance, above note 15, pp. 38–39.

72 Melzer, Nils, “Direct Participation in Hostilities”, in Dražan Djukić and Niccolò Pons (eds), The Companion to International Humanitarian Law, Brill, Leiden, 2018, p. 300Google Scholar. See also 2003 DPH Report, above note 64, p. 9 (“No one contested that direct participation in hostilities by a civilian could not be considered a war crime”); Schmitt, Michael N., “Humanitarian Law and Direct Participation in Hostilities by Private Contractors or Civilian Employees”, Chicago Journal of International Law, Vol. 5, 2005, pp. 520–521Google Scholar (arguing that while mere direct participation, without more, is not a war crime, the acts underlying direct participation may be punishable).

73 See ICRC Interpretive Guidance, above note 15, p. 84 fn. 226 (with references). Reportedly, the drafters of the 1998 Rome Statute of the ICC did not even consider any proposal to include direct participation in hostilities as a war crime in the Statute. See A. Rogers, above note 67, p. 122 fn. 100.

74 Tallinn Manual 2.0, above note 22, Rule 86.

75 For a comparative analysis of cyber crime offences criminalized by national laws around the world, see UN Office on Drugs and Crime, Comprehensive Study on Cybercrime, February 2013, pp. 77–106, available at: www.unodc.org/documents/organized-crime/UNODC_CCPCJ_EG.4_2013/CYBERCRIME_STUDY_210213.pdf.

76 M. Bothe, K. J. Partsch and W. A. Solf, above note 35, p. 278; ICRC Interpretive Guidance, above note 15, p. 84.

77 See e.g. Ipsen, Knut, “Combatants and Non-Combatants”, in Dieter Fleck (ed.), The Handbook of International Humanitarian Law, 4th ed., Oxford University Press, Oxford, 2021, p. 97Google Scholar.

78 ICRC Commentary on the APs, above note 13, p. 619, para. 1944; ICRC Interpretive Guidance, above note 15, p. 69; Program on Humanitarian Policy and Conflict Research, HPCR Manual on International Law Applicable to Air and Missile Warfare, Harvard University, 15 May 2009, chapeau to section F; Tallinn Manual 2.0, above note 22, Rule 91, commentary para. 1; UK Military Manual, above note 17, para. 5.3.2; DoD Military Manual, above note 17, para. 16.5.5.

79 Tallinn Manual 2.0, above note 22, Rule 97, commentary para. 3.

80 See, generally, Ramsden, Michael, “Targeted Killings and International Human Rights Law: The Case of Anwar Al-Awlaki”, Journal of Conflict and Security Law, Vol. 16, No. 2, 2011CrossRefGoogle Scholar; Pejic, Jelena, “Extraterritorial Targeting by Means of Armed Drones: Some Legal Implications”, International Review of the Red Cross, Vol. 96, No. 893, 2014, especially pp. 70–75CrossRefGoogle Scholar, 100–101. Discussing these areas of law is outside of the scope of the present article.

81 AP I, Art. 51(3); Protocol Additional (II) to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of Non-International Armed Conflicts, 1125 UNTS 609, 8 June 1977 (entered into force 7 December 1978) (AP II), Art. 13(3); ICRC Customary Law Study, above note 12, Rule 6.

82 ICRC Interpretive Guidance, above note 15, p. 70.

83 Ibid., p. 65.

84 For an analysis of the temporal element in the context of technology companies’ involvement in armed conflicts (scenario 3), see J. Horowitz, above note 7.

85 See the above section on “Application of the General Rule to the Three Scenarios”.

86 See also Tallinn Manual 2.0, above note 22, Rule 97, commentary para. 4: “In the cyber context, it is essential to emphasize that an ‘act’ is required by the individual concerned.”

87 See also Supreme Court of Israel, Public Committee against Torture, above note 12, para. 39: “A civilian taking a direct part in hostilities one single time, or sporadically, who later detaches himself from that activity, is a civilian who, starting from the time he detaches himself from that activity, is entitled to protection from attack.”

88 The device containing this information may continue to qualify as a military objective if fulfils the definition of military objective in the circumstances ruling at the time: see AP I, Art. 52(2). For example, if the information stored in the device was outdated or had otherwise lost its military value, the device would not qualify as a military objective as its destruction, capture or neutralization would no longer offer a “definite military advantage” as required by the law. See, further, ICRC Commentary on the APs, above note 13, p. 636, para. 2024.

89 See ICRC Commentary on the APs, above note 13, p. 1453, para. 4789, noting that protection is denied “for as long as [the individual's] participation lasts. Thereafter, as he no longer presents any danger for the adversary, he may not be attacked.” See also M. Bothe, K. J. Partsch and W. A. Solf, above note 35, p. 342: “while participating directly in hostilities[, civilians] present an immediate threat to the adverse Party and, accordingly, they are subject to direct attack to the same extent as combatants”.

90 AP I, Art. 57(2)(a)(i); ICRC Customary Law Study, above note 12, Rule 16.

91 See above note 62.

92 Dinstein, Yoram, The Conduct of Hostilities under the Law of International Armed Conflict, 4th ed., Cambridge University Press, Cambridge, 2022, p. 206CrossRefGoogle Scholar, quoting Frits Kalshoven, Reflections on the Law of War: Collected Essays, Cambridge University Press, Cambridge, 2007, pp. 73–74.

93 See AP I, Arts 51(5)(b), 57(2)(a)(iii); ICRC Customary Law Study, above note 12, Rule 14.

94 See AP I, Art. 57(3); ICRC Customary Law Study, above note 12, Rule 21.

95 AP I, Art. 50(3).

96 See also J. Horowitz, above note 7, endorsing the same policy preference while warning that cyber operations against military objectives that also provide services to civilians pose significant potential risks, in particular when they are detrimental to critical infrastructure that supports essential civilian services such as health care, electricity and water.

97 ICJ, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 8 July 1996, ICJ Reports 1996 (Nuclear Weapons Advisory Opinion), para. 78.

98 Max Weber, The Vocation Lectures, Hackett, Indianapolis, IN, 2004, p. 33: “the state is the form of human community that … lays claim to the monopoly of legitimate violence within a particular territory”.

99 Jean-Jacques Rousseau, The Social Contract, trans. G. D. H. Cole, Cosimo Classics, New York, 2008 (first published 1762), pp. 19–20.

100 See e.g. UNGA Res. 2444 (XXIII), 19 December 1968, para. 1(c): “distinction must be made at all times between persons taking part in the hostilities and members of the civilian population to the effect that the latter be spared as much as possible”.

101 Report of the Group of Governmental Experts on Advancing Responsible State Behaviour in Cyberspace in the Context of International Security, UN Doc. A/76/135, 14 July 2021; UNGA Res. 76/19, 8 December 2021, para. 2; Report of the Group of Governmental Experts on Developments in the Field of Information and Telecommunications in the Context of International Security, UN Doc. A/70/174, 22 July 2015, para. 28(d); UNGA Res. 73/27, 11 December 2018, para. 1.

102 ICRC, “Principles of IHL (Distinction, Proportionality) Have Direct Bearing on Cyber Operations”, Statement to the UN Open-Ended Working Group on Developments in the Field of Information and Telecommunications in the Context of International Security, 12 February 2020, available at: www.icrc.org/en/document/principles-international-humanitarian-law-distinction-proportionality-have-direct-bearing.

103 See e.g. Burkle, Frederick M., “Revisiting the Battle of Solferino: The Worsening Plight of Civilian Casualties in War and Conflict”, Disaster Medicine and Public Health Preparedness, Vol. 13, No. 5–6, 2019, p. 838CrossRefGoogle ScholarPubMed.

104 Jensen, Eric Talbot, “Applying a Sovereign Agency Theory of the Law of Armed Conflict”, Chinese Journal of International Law, Vol. 12, 2012, p. 701 fn. 74Google Scholar.

105 French Position Paper, above note 20, p. 15.

106 See e.g. Eichensehr, Kristen E., “The Law and Politics of Cyberattack Attribution”, UCLA Law Review, Vol. 67, 2020, p. 529Google Scholar.

107 See e.g. Dan Bilefsky, “A Ukrainian Appeals Court Reduces the Life Sentence of a Russian Soldier Tried for War Crimes”, New York Times, 29 July 2022.

108 See e.g. Gabor Rona, “When Considering CIA Targeted Killings, Don't Forget International Law!”, Just Security, 5 April 2016, available at: www.justsecurity.org/30426/cia-targeted-killings-dont-forget-international-law/ (“blurring the lines between combatant and civilian – as occurs when the CIA directly participates in hostilities – creates a precedent that undermines the principle of distinction, even if that participation is not unlawful”); Sassòli, Marco, International Humanitarian Law: Rules, Controversies, and Solutions to Problems Arising in Warfare, Edward Elgar, Cheltenham, 2019, p. 25CrossRefGoogle Scholar (“the increasing civilianization of armed forces is … eroding the principle of distinction because individuals outside of the armed forces are increasingly performing several functions that contribute not only to a State's military capacity but even directly to battlefield action”); D. Wallace, S. Reeves and T. Powell, above note 38, p. 174 (“civilian involvement in armed conflicts … undermines the [law of armed conflict's] core principle of distinction”).

109 AP I, Art. 48; ICRC Customary Law Study, above note 12, Rule 1.

110 K. Mačák, above note 8, p. 421.

111 Bartolini, Giulio, “The Participation of Civilians in Hostilities”, in Michael John Matheson and Djamchid Momtaz (eds), Rules and Institutions of International Humanitarian Law Put to the Test of Recent Armed Conflicts, Martinus Nijhoff, Leiden, 2010, p. 325Google Scholar.

112 Ibid., p. 357.

113 Cameron, Lindsey and Chetail, Vincent, Privatizing War, Cambridge University Press, Cambridge, 2013, p. 104CrossRefGoogle Scholar (emphasis added).

114 ICRC Commentary on the APs, above note 13, p. 598, para. 1863: “The basic rule of protection and distinction is confirmed in this article.”

115 AP I, Art. 57(1); ICRC Customary Law Study, above note 12, Rule 15.

116 French Position Paper, above note 20, p. 15.

117 German Position Paper, above note 21, p. 9.

118 ICRC, International Humanitarian Law and Cyber Operations during Armed Conflicts, ICRC Position Paper, Geneva, November 2019, p. 6, available at: www.icrc.org/en/download/file/108983/icrc_ihl-and-cyber-operations-during-armed-conflicts.pdf.

119 Tallinn Manual 2.0, above note 22, Rule 114, commentary para. 4. Similarly, see Laurent Gisel, Tilman Rodenhäuser and Knut Dörmann, “Twenty Years On: International Humanitarian Law and the Protection of Civilians against the Effects Of Cyber Operations during Conflicts”, Armed, International Review of the Red Cross, Vol. 102, No. 913, 2020, p. 324Google Scholar: “This obligation requires all those involved in military operations to continuously bear in mind the effects of military operations on the civilian population, civilians and civilian objects, to take steps to reduce such effects as much as possible, and to seek to avoid any unnecessary effects.”

120 AP I, Art. 58(c).

121 French Position Paper, above note 20, p. 16.

122 Tallinn Manual 2.0, above note 22, Rule 121, commentary para. 9.

123 See e.g. Inter-American Commission on Human Rights, Third Report on Human Rights Situation in Colombia, OEA/Ser.L/V/II.102, Doc. 9, Rev. 1, 26 February 1999, para. 54 (“by virtue of their hostile acts, such civilians lose the benefits pertaining to peaceable civilians of precautions in attack and against the effects of indiscriminate or disproportionate attacks”); Supreme Court of Israel, Public Committee against Torture, above note 12, para. 46 (holding that the proportionality requirements do not cover the harm “to a civilian taking a direct part in the hostilities at such time as the harm is caused”).

124 See also the text at above notes 103–112, noting that such practices increase the risk for other, protected civilians of being incidentally harmed or erroneously targeted.

125 AP I, Art. 77(2); AP II, Art. 4(3)(c); ICRC Customary Law Study, above note 12, Rule 137; Convention on the Rights of the Child, 1577 UNTS 3, 20 November 1989 (entered into force 2 September 1990), Art. 38(2). Under the 1998 Rome Statute of the ICC, using children to “participate actively in hostilities” constitutes a war crime in both international and non-international armed conflicts. Rome Statute of the International Criminal Court, UN Doc. A/CONF.183/9, 17 July 1998 (entered into force 1 July 2002), Arts 8(2)(b)(xxvi), 8(2)(e)(vii).

126 ICRC Commentary on the APs, above note 13, p. 901, para. 3187.

127 African Charter on the Rights and Welfare of the Child, July 1990 (entered into force 29 November 1999), Art. 22(2). Article 2 of the Charter states that “[f]or the purposes of this Charter, a child means every human being below the age of 18 years”.

128 Resolution 2 of the 26th International Conference of the Red Cross and Red Crescent in 1995 recommended that parties to conflict “take every feasible step to ensure that children under the age of 18 years do not take part in hostilities”.

129 See the above section entitled “From General Trends to Qualitative and Quantitative Shifts in the Digital Space”.

130 See Pontus Winther, “Military Influence Operations and IHL: Implications of New Technologies”, Humanitarian Law and Policy Blog, 27 October 2017, available at: https://blogs.icrc.org/law-and-policy/2017/10/27/military-influence-operations-ihl-implications-new-technologies/.

131 Guidance is available regarding the adoption of measures that provide for age-appropriate child safety in digital applications. See e.g. International Telecommunication Union, Guidelines for Policy-Makers on Child Online Protection, Geneva, 2020, p. 44 on tools, services and settings.

132 See e.g. Greenwood, Christopher, “Human Rights and Humanitarian Law – Conflict or Convergence?”, Case Western Reserve Journal of International Law, Vol. 43, No. 1–2, 2010, p. 495Google Scholar.

133 See Mačák, Kubo, “The Role of International Human Rights Law in the Interpretation of the Fourth Geneva Convention”, Israel Yearbook on Human Rights, Vol. 52, 2022, p. 223Google Scholar.

134 See e.g. Nuclear Weapons Advisory Opinion, above note 97, para. 25; ICJ, Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, 9 July 2004, ICJ Reports 2004, para. 106; ICJ, Armed Activities on the Territory of the Congo (Democratic Republic of the Congo v. Uganda), Judgment, 19 December 2005, ICJ Reports 2005, paras 215–220.

135 See e.g. Duffy, Helen, “Trials and Tribulations: Co-Applicability of IHL and Human Rights in an Age of Adjudication”, in Ziv Bohrer, Janina Dill and Helen Duffy (eds), Law Applicable to Armed Conflict, Cambridge University Press, Cambridge, 2020, p. 39Google Scholar.

136 See e.g. Israel, “Comments from the State of Israel on the International Law Commission's Draft Principles on the Protection of the Environment in Relation to Armed Conflicts as Adopted by the Commission in 2019 on First Reading”, 2020, para. 9.

137 ILC, Draft Articles on the Effects of Armed Conflicts on Treaties, 2011, reprinted in Yearbook of the International Law Commission, Vol. 2, Part 2, 2011, pp. 126–127, paras 49–50.

138 See e.g. Human Rights Committee, General Comment No. 31, “Nature of the General Legal Obligation on States Parties to the Covenant”, UN Doc. CCPR/C/21/Rev.1/Add. 13, 26 May 2004, para. 11; Human Rights Committee, General Comment No. 35, “Article 9: Liberty and Security of Person”, UN Doc. CCPR/C/GC/35, 16 December 2014, para. 64; Human Rights Committee, General Comment No. 36, “Article 6: Right to Life”, UN Doc. CCPR/C/GC/36, 3 September 2019 (General Comment 36), para. 64; Committee on Economic, Social and Cultural Rights, “Concluding Observations: Israel”, UN Doc. E/C.12/1/Add.90, 26 June 2003, para. 31; Committee against Torture, General Comment No. 2, “Implementation of Article 2 by States Parties”, UN Doc. CAT/C/GC/2, 24 January 2008, para. 5; Committee on the Elimination of Discrimination against Women, “General Recommendation No. 28 on the Core Obligations of States parties under Article 2 of the Convention on the Elimination of All Forms of Discrimination against Women”, UN Doc. CEDAW/C/GC/28, 16 December 2010, para. 11.

139 See the above section on “Loss of Protection from Attack and the Related Safeguards”.

140 ECtHR, Mamatkulov and Askarov v. Turkey, Appl. Nos 46827/99, 46951/99, Judgment (Merits and Just Satisfaction) (Grand Chamber), 4 February 2005, para. 67 (emphasis added).

141 General Comment 36, above note 138, para. 3.

142 Ibid., para. 64. See also ICRC Interpretive Guidance, above note 15, p. 11, noting that the Guidance deals with direct participation in hostilities under an IHL lens only, without prejudice to other bodies of law – such as IHRL – that may concurrently be applicable in a given situation.

143 See the above section on “Legal Implications for States: International Humanitarian Law”.

144 General Comment 36, above note 138, para. 64.

145 Diakonia, Forcible Recruitment of Adults by Non-State Armed Groups in Non-International Armed Conflict, Legal Brief, May 2019, p. 3.

146 Y. Dinstein, above note 92, pp. 199–200.

147 See e.g. M. Sassòli, above note 108, p. 2; Y. Dinstein, above note 92, pp. 199–200.

148 ECtHR, Nicolae Virgiliu Tănase v. Romania, Appl. No. 41720/13, Judgment (Grand Chamber), 25 June 2019, para. 140.

149 ECtHR, Mučibabić v. Serbia, Appl. No. 34661/07, Judgment (Third Section), 12 July 2016, para. 126 (concerning the death of eleven individuals in the context of covert production of rocket fuel under the auspices of a government intelligence service).

150 See text at above note 34.

151 ECtHR, Lambert and Others v. France, Appl. No. 46043/14, Judgment (Grand Chamber), 5 June 2015, para. 142.

152 See e.g. ECtHR, Öneryıldız v. Turkey, Appl. No. 48939/99, Judgment (Grand Chamber), 30 November 2004, para. 108 (substantiating a finding of a violation of the right to life – in the context of dangerous industrial activities – in part on the fact that the State had “not shown that any measures were taken in the instant case to provide the [applicants] with information enabling them to assess the risks they might run as a result of the choices they had made”); ECtHR, L.C.B. v. United Kingdom, Appl. No. 14/1997/798/1001, Judgment, 9 June 1998, para. 38 (considering that a State may violate its obligation to safeguard the right to life if it does not inform individuals under its jurisdiction about a real risk to their health that is known to that State). See also ECtHR, Vilnes and Others v. Norway, Appl. Nos 52806/09, 22703/10, Judgment (First Section), 5 December 2013, paras 233–245 (holding that the State violated the applicants’ right to respect for their private life by failing to ensure that they received essential information enabling them to assess the risks to their health and safety entailed in a dangerous activity authorized by the State).

153 W. B. Yeats, “The Second Coming”, 1919.