1 Gary Sheftick, ‘Smart Sensor Network Helps Redirect Missile”, 18 September 2019, available at: www.army.mil/article/226890/smart_sensor_network_helps_redirect_missile (all internet references were accessed in October 2021).

2 Schmitt, Michael N. and Thurnher, Jeffrey S., “‘Out of the Loop’: Autonomous Weapon Systems and the Law of Armed Conflict”, Harvard National Security Journal, Vol. 4, No. 2, 2013, p. 234Google Scholar. Of course, in determining whether a capability is already “here” or not, much will depend on the starting point – its definition.

3 Final Report of the Panel of Experts on Libya Established Pursuant to Security Council Resolution 1973 (2011), UN Doc. S/2021/229, 8 March 2021, para. 63.

4 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. 58; 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 22, available at: https://ihl-databases.icrc.org/customary-ihl/eng/docs/v1.

5 Burri, Susanne, “Why Moral Theorizing Needs Real Cases: The Redirection of V-Weapons during the Second World War”, Journal of Political Philosophy, Vol. 28, No. 2, 2020, p. 247CrossRefGoogle Scholar.

6 Ibid., pp. 254 ff.

7 US Government Accountability Office, Weapon Systems Cybersecurity: DOD Just Beginning to Grapple with Scale of Vulnerabilities, Report to the Committee on Armed Services, 2018, available at: www.gao.gov/assets/gao-19-128.pdf.

8 Group of Governmental Experts on Emerging Technologies in the Area of Lethal Autonomous Weapons Systems, Report of the 2019 Session, UN Doc. CCW/GGE.1/2019/3, 25 September 2019, para. 25(a) and Guiding Principle (f).

9 A3I stands for architecture, automation, autonomy and interfaces.

10 G. Sheftick, above note 1.

11 Jeffrey B. Jones, “Confronting China's Efforts to Steal Defense Information”, Belfer Center Paper, May 2020, available at: www.belfercenter.org/sites/default/files/2020-05/ChinaStealing.pdf.

12 International Court of Justice, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, ICJ Reports 1996 (Nuclear Weapons Advisory Opinion), para. 78.

13 AP I, Art. 51(1).

14 Yves Sandoz, Christophe Swinarski and Bruno Zimmermann (eds), Commentary on the Additional Protocols, ICRC, Geneva, 1987 (ICRC Commentary on the APs), para. 1935.

15 Théo Boutruche, “Expert Opinion on the Meaning and Scope of Feasible Precautions under International Humanitarian Law and Related Assessment of the Conduct of the Parties to the Gaza Conflict in the Context of the Operation ‘Protective Edge’”, Expert Opinion commissioned by Diakonia, 2015, p. 7.

16 AP I, Art. 48.

17 Ibid., Art. 35(1).

18 Ibid., Art. 57.

19 ICRC Commentary on the APs, above note 14, para. 2241.

20 ICRC Customary Law Study, above note 4, Rule 22.

21 ICRC Commentary in the APs, above note 14, para. 2239.

22 Dieter Fleck (ed.), The Handbook of International Humanitarian Law, 4th ed., Oxford University Press, Oxford, 2021, Section 8.09, para. 2.

23 Eric Jensen, “Precautions against the Effects of Attacks in Urban Areas”, International Review of the Red Cross, Vol. 98, No. 1, 2016, pp. 164–165.

24 Ibid.

25 T. Boutruche, above note 15, p. 17.

26 Ibid., pp. 15–16.

27 This was the view expressed by a number of delegations upon ratification of AP I. See Gaudreau, Julie, “The Reservations to the Protocols Additional to the Geneva Conventions for the Protection of War Victims”, International Review of the Red Cross, Vol. 85, No. 849, 2003, pp. 156–157Google Scholar.

28 Sassòli, Marco and Quintin, Anne, “Active and Passive Precautions in Air and Missile Warfare”, Israel Yearbook on Human Rights, Vol. 44, 2014, p. 82Google Scholar. In the context of precautions in attack, we read in a report submitted to the International Criminal Tribunal for the former Yugoslavia (ICTY) that “[t]he obligation to do everything feasible is high but not absolute”. Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign against the Federal Republic of Yugoslavia, 8 June 2000, para. 29.

29 Ibid., p. 83.

30 Quéguiner, Jean-François, “Precautions under the Law Governing the Conduct of Hostilities”, International Review of the Red Cross, Vol. 88, No. 864, 2006, p. 802CrossRefGoogle Scholar.

31 M. Sassòli and A. Quintin, above note 28, p. 87.

32 ICRC Commentary on the APs, above note 14, para. 2257.

33 AP I, Art. 51(2).

34 Ibid., Art. 51(5)(b).

35 International Criminal Court (ICC), Situation in the Democratic Republic of the Congo in the Case of the Prosecutor v. Bosco Ntaganda, Observations by Professor Roger O'Keefe Pursuant to Rule 103 of the Rules of Procedure and Evidence, No. ICC-01/04-02/06 A2, 17 September 2020 (O'Keefe Observations), p. 3.

36 ICRC Commentary on the APs, above note 14, para. 1879.

37 Ibid., para. 1880.

38 ICC, Situation in the Democratic Republic of the Congo in the Case of the Prosecutor v. Bosco Ntaganda, Submission of Observations to the Appeals Chamber Pursuant to Rule 103 by Geoffrey Corn et al., No. ICC-01/04-02/06 A2, 18 September 2020, paras 14–15. The authors provide a number of scenarios that distinguish between acts that would amount to an attack and acts that would not: “providing air-delivered supplies such as food or medical equipment may inadvertently cause injury or damage if the air-delivered material lands on a person or structure”, “maneuver damage to roads and fields”.

39 In the Galić case, the ICTY only reviewed subjective elements related to the direction of attacks against civilians as additional and separate from the term “attack”. ICTY, Prosecutor v. Stanislav Galić, Case No. IT-98-29-T, Judgment (Trial Chamber), 5 December 2003, paras 41 ff. See also ICTY, Prosecutor v. Pavle Strugar, Case No. IT-01-41-T, Judgment (Trial Chamber), 31 January 2005, para. 282. The International Criminal Court (ICC) has also left any analysis of subjective elements beyond the definition of “attack”: see ICC, Prosecutor v. Bosco Ntaganda, Case No. ICC-01/04-02/06, Judgment (Trial Chamber), 8 July 2019, para. 916; ICC, Prosecutor v. Germain Katanga, Case No. ICC-01/04-01/07, Judgment (Trial Chamber), 7 March 2014, para. 798.

40 The Appeals Chamber summarized the Trial Chamber's reasoning, the submissions received, and the opinions of the individual judges without giving a unified or detailed view of the meaning of “attack”: see ICC, Prosecutor v. Bosco Ntaganda, Case No. ICC-01/04-02/06, Judgment (Appeals Chamber), 30 March 2021, paras. 1149–1169.

41 ICC, Prosecutor v. Bosco Ntaganda, No. ICC-01/04-02/06 A A2, Judgment (Appeals Chamber), Partly Concurring Opinion of Judge Eboe-Osuji, 30 March 2021, para. 110.

42 Michael N. Schmitt (ed.), Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations, Cambridge University Press, Cambridge, 2017, Rule 92.

43 Yoram Dinstein and Arne Willy Dahl, Oslo Manual on Select Topics of the Law of Armed Conflict: Rules and Commentary, Springer, Cham, 2020 (Oslo Manual), Rule 8.

44 ICC, Ntaganda, above note 40, para. 1166.

45 See, for instance, ICC, Ntaganda, above note 39, paras 916–917.

46 Michael N. Schmitt and Lt.-Col. Matthew King, “The ‘Shift Cold’ Military Tactic and International Humanitarian Law”, Just Security, 20 February 2018, available at: www.justsecurity.org/52198/shift-cold-tactic-international-humanitarian-law/.

47 Ibid.

48 Ibid.

49 Adil Ahmad Haque, “The ‘Shift Cold’ Military Tactic: Finding Room under International Law”, Just Security, 20 February 2018, available at: www.justsecurity.org/52713/shift-cold-military-tactic-finding-room-under-international-law/.

50 Ibid.

51 This conflict of obligations would be a real concern for attackers, as attackers are required under Article 57 of AP I to cancel or suspend attacks if, inter alia, it becomes apparent that the objective is not a military one.

52 T. Boutruche, above note 15, p. 11.

53 AP I, Art. 57(5).

54 Richard Gardiner, “The Vienna Convention Rules on Treaty Interpretation”, in Duncan Hollis (ed.), The Oxford Guide to Treaties, Oxford University Press, Oxford and New York, 2020, p. 460.

55 Ibid., pp. 465–466.

56 Consider, for instance, redirection towards an empty field. As Dinstein notes, “one result of the negative definitional methodology is that some objects are deemed ‘civilian’ – even when stricto sensu they are not civilian in the dictionary meaning of the word – simply because they are not military objectives”. Yoram Dinstein, The Conduct of Hostilities under the Law of International Armed Conflict, Cambridge University Press, Cambridge, 2016, p. 381.

57 Oslo Manual, above note 43, Commentary to Rule 45.

58 In the trolley problem, a trolley is heading towards a group of five people, and it will cause their death unless it gets redirected to another track, where only one person is present. See Thomson, Judith Jarvis, “The Trolley Problem”, Yale Law Journal, Vol. 94, No 6, 1985, p. 1395CrossRefGoogle Scholar.

59 O'Keefe Observations, above note 35, pp. 3–4. See also ICRC Commentary on the APs, above note 14, para. 1890.

60 “One might characterize the two branches as concurrent, coexisting, consistent, convergent, coterminous, congruent, confluent, corresponding, cumulative, complementary, compatible, cross-fertilizing, contradictory, competitive, or even in conflict.” Andrew Clapham, “The Complex Relationship between the 1949 Geneva Conventions and International Human Rights Law”, in Andrew Clapham, Paola Gaeta and Marco Sassòli (eds), The 1949 Geneva Conventions: A Commentary, Oxford University Press, Oxford and New York, 2015.

61 Orakhelashvili, Alexander, “The Interaction between Human Rights and Humanitarian Law: Fragmentation, Conflict, Parallelism, or Convergence?”, European Journal of International Law, Vol. 19, No. 1, 2008CrossRefGoogle Scholar; Sassòli, Marco and Olson, Laura, “The Relationship between International Humanitarian Law and Human Rights Law Where It Matters: Admissible Killing and Internment of Fighters in Non-International Armed Conflicts”, International Review of the Red Cross, Vol. 90, No. 871, 2008CrossRefGoogle Scholar; Françoise Hampson, “The Relationship between International Humanitarian Law and International Human Rights Law”, in Scott Sheeran and Nigel S. Rodley (eds), Routledge Handbook of International Human Rights Law, Routledge, Abingdon, 2013.

62 Clapham, Andrew, “Human Rights in Armed Conflict: Metaphors, Maxims, and the Move to Interoperability”, Human Rights & International Legal Discourse, Vol. 12, No. 1, 2018, p. 11Google Scholar.

63 Jens David Ohlin, “Introduction: The Inescapable Collision”, in J. D. Ohlin (ed.), Theoretical Boundaries of Armed Conflict and Human Rights, Cambridge University Press, Cambridge, 2016, p. 21.

64 Nuclear Weapons Advisory Opinion, above note 12, para. 25: “In principle, the right not arbitrarily to be deprived of one's life applies also in hostilities. The test of what is an arbitrary deprivation of life, however, then falls to be determined by the applicable lex specialis, namely, the law applicable in armed conflict which is designed to regulate the conduct of hostilities.” This approach is also followed by human rights bodies, including in European Court of Human Rights (ECtHR), Hassan v. UK, Appl. No. 29750/09, Judgment (Grand Chamber), 16 September 2014.

65 This is a point of particular importance, as provisions under IHRL may differ significantly across treaty instruments.

66 ECtHR, Hassan, above note 64, para. 102; but see criticism of the way the Court approached this “accommodation”, in ECtHR, Hassan v. UK, Appl. No. 29750/09, Judgment (Grand Chamber), Partly Dissenting Opinion of Judge Spano et al., 16 September 2014, paras 16–17; Lawrence Hill-Cawthorne, “The Grand Chamber Judgment in Hassan v UK”, EJIL: Talk!, 16 September 2014, available at: www.ejiltalk.org/the-grand-chamber-judgment-in-hassan-v-uk/.

67 Jens David Ohlin, “Acting as a Sovereign Versus Acting as a Belligerent”, in J. D. Ohlin (ed.), above note 63, p. 129: “[B]elligerent powers flow from actions that regulate the armed conflict between two co-equal belligerents, while sovereign powers regulate the subjects under the government's control. The distinction between the modes of action might overlap in discrete situations – requiring a legal principle (such as lex specialis) to resolve the potential conflict.”

68 Marko Milanovic, “The Lost Origins of Lex Specialis: Rethinking the Relationship between Human Rights and International Humanitarian Law”, in J. D. Ohlin (ed.), above note 63, p. 107.

69 Robert Kolb, “Human Rights and Humanitarian Law”, in Max Planck Encyclopedia of Public International Law, March 2013, paras 35–37.

70 Human Rights Committee, General Comment No. 36, “Article 6: Right to Life”, UN Doc. CCPR/C/GC/36, 30 October 2018, para. 64.

71 European Convention on Human Rights, ETS 5, 4 November 1950, Art. 2(2).

72 ECtHR, Isayeva, Yusupova and Bazayeva v. Russia, Appl. Nos 57947/00, 57948/00, 57949/00, Judgment, 6 July 2005, para. 169.

73 The other aims being “(b) in order to effect a lawful arrest or to prevent the escape of a person lawfully detained” and “(c) in action lawfully taken for the purpose of quelling a riot or insurrection”.

74 ECtHR, Bubbins v. UK, Appl. No. 50196/99, Judgment, 17 March 2005, para. 138.

75 ECtHR, Finogenov v. Russia, Appl. Nos 18299/03, 27311/03, Judgment, 20 December 2011, para. 226.

76 ECtHR, Isayeva, above note 72, para. 181; ECtHR, Andronicou and Constantinou v. Cyprus, Appl. No. 25052/94, Judgment, 9 October 2007, para. 192.

77 See German Federal Constitutional Court, Aviation Security Act case, 1 BvR 357/05, Judgment (First Senate), 15 February 2006.

78 Kai Moller, “The Right To Life between Absolute and Proportional Protection”, LSE Law, Society and Economy Working Paper, 2010, p. 15.

79 ECtHR, Isayeva, above note 72, para. 178.

80 For example, if there is debris that imperils the life of individuals, obligations to protect persons from threats may become relevant: “The obligation of States parties to respect and ensure the right to life extends to reasonably foreseeable threats and life-threatening situations that can result in loss of life.” Human Rights Committee, above note 70, para. 7.

81 ECtHR, Varnava et al. v. Turkey, Appl. Nos 16064/90, 16065/90, 16066/90, Judgment (Grand Chamber), 18 September 2009, para. 185.

82 On the difficulties of applying the proportionality test under IHL in the 2021 violence in Gaza, for instance, see Alonso Gurmendi, “The Rabbit Hole, from Antwerp to Gaza”, Opinio Juris, 19 May 2021, available at: http://opiniojuris.org/2021/05/19/the-rabbit-hole-from-antwerp-to-gaza/.

83 Similar concerns were raised in the Aviation Security Act case, above note 77, paras 125–129.

84 Human Rights Committee, above note 70, para. 70. Such thinking can already be found in individual opinions of judges at the ECtHR: see ECtHR, Georgia v. Russia (II), Appl. No. 38263/08, Judgment (Grand Chamber), Concurring Opinion of Judge Keller, 21 January 2021, para. 27. Of course, each side will argue that the other is breaching jus ad bellum, and therefore that there is unlawful violence.

85 Carl von Clausewitz, On War, Project Gutenberg, 1946, p. 54.