1 The Guardian, “The Man Who Wrote the Rules of War”, 12 August 1999, available at: www.theguardian.com/theguardian/1999/aug/12/features11.g2 (all internet references were accessed in October 2022).

2 Oxford Learner's Dictionaries, Oxford University Press, Oxford, 2022, available at: www.oxfordlearnersdictionaries.com/.

3 ICRC, “War and International Humanitarian Law”, 29 October 2010, available at: www.icrc.org/eng/war-and-law/overview-war-and-law.htm.

4 On the concept of “object and purpose”, see, for example, ICRC, Commentary of 2020 on Convention (III) relative to the Treatment of Prisoners of War. Geneva, 12 August 1949, Introduction, paras 87, 88 and 91, available at: https://ihl-databases.icrc.org/applic/ihl/ihl.nsf/Comment.xsp?action=openDocument&documentId=1B9A4ABF10E7EAD2C1258585004E7F19.

5 For an overview of the sources of IHL, see Henckaerts, Jean-Marie, “History and Sources”, in Saul, Ben and Akande, Dapo (eds), The Oxford Guide to International Humanitarian Law, Oxford University Press, Oxford, 2020, pp. 1–2Google Scholar; Crawford, Emily, Non-Binding Norms in International Humanitarian Law, Oxford University Press, Oxford, 2022Google Scholar. While a primary source of IHL, general principles will not be addressed in this article.

6 See Paul Tavernier, “L'évolution du droit international humanitaire au XXI^ème siècle : une nécessité?”, in The International Legal Order: Current Needs and Possible Responses. Essays in Honour of Djamchid Momtaz, Brill Nijhoff, Leiden and Boston, MA, 2017, p. 734.

7 Sivakumaran, Sandesh, “Beyond States and Non-State Actors: The Role of State-Empowered Entities in the Making and Shaping of International Law”, Columbia Journal of Transnational Law, Vol. 55, No. 2, 2017, pp. 392–3Google Scholar.

8 For a historical overview of IHL's early stages, see Best, Geoffrey, War and Law Since 1945, Clarendon, Oxford, 1994, pp. 14–34Google Scholar. See also Witt, John Fabian, Lincoln's Code: The Laws of War in American History, Free Press, New York, 2012Google Scholar.

9 Convention for the Amelioration of the Condition of the Wounded in Armies in the Field, Geneva, 22 August 1864 (entered into force 22 June 1865).

10 Bugnion, François, “The International Committee of the Red Cross and the Development of International Humanitarian Law”, Chicago Journal of International Law, Vol. 5, No. 1, 2004, p. 193Google Scholar. The Convention of 1864 was replaced by the Geneva Conventions of 1906, 1929 and ultimately 1949 on the same subject; Convention for the Amelioration of the Condition of the Wounded and Sick in Armies in the Field, Geneva, 6 July 1906 (entered into force 9 August 1907); Convention for the Amelioration of the Condition of the Wounded and Sick in Armies in the Field, Geneva, 27 July 1929.

11 Declaration Renouncing the Use, in Time of War, of Explosive Projectiles Under 400 Grammes Weight, Saint Petersburg, 29 November/11 December 1868 (entered into force 11 December 1868); Robert Kolb and Momchil Milanov, “The 1868 St Petersburg Declaration on Explosive Projectiles: A Reappraisal”, Journal of the History of International Law, Vol. 20, No. 4, 2018, p. 517. The declaration was based on reciprocity, so (intentionally) not applicable to “colonial warfare”; see R. Kolb and M. Milanov, ibid., p. 520.

12 Hans-Peter Gasser, “A Look at the Declaration of St. Petersburg of 1868”, International Review of the Red Cross, No. 297, 1993.

13 Michael Riepl, Russian Contributions to International Humanitarian Law, Nomos, Baden-Baden, 2022, pp. 33–41.

14 Convention (II) with Respect to the Laws and Customs of War on Land and its annex: Regulations concerning the Laws and Customs of War on Land. The Hague, 29 July 1899 (entered into force 4 September 1900); Convention (IV) respecting the Laws and Customs of War on Land and its annex: Regulations Concerning the Laws and Customs of War on Land. The Hague, 18 October 1907 (entered into force 26 January 1910). See Best, Geoffrey, “Peace Conferences and the Century of Total War: The 1899 Hague Conference and What Came After”, International Affairs, Vol. 75, No. 3, 1999CrossRefGoogle Scholar.

15 “International Military Tribunal (Nuremberg), Judgment and Sentences”, American Journal of International Law, Vol. 41, No. 1, 1947, pp. 248–9. Many of the rules codified in this convention were later codified and expanded on in the two Additional Protocols to the Geneva Conventions of 1977: 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); 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).

16 Daniel Palmieri, “The International Committee of the Red Cross in the First World War”, ICRC, 10 September 2014, available at: www.icrc.org/en/document/international-committee-red-cross-first-world-war-0.

17 Protocol for the Prohibition of the Use of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare, Geneva, 17 June 1925 (entered into force 8 February 1928). The protocol was adopted in the aftermath of the First World War, which saw the widespread use of poison gas despite a prohibition already included in the 1899 Hague Convention. As a result of its adoption, civilians and combatants were largely spared this horrific fate during the Second World War.

18 Convention relative to the Treatment of Prisoners of War, Geneva, 27 July 1929. The Convention was adopted to overcome lacunae and imprecisions in existent protections of prisoners of war contained in the Hague Regulations of 1899 and 1907.

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

20 On the drafting history of the four Geneva Conventions, see, among others, G. Best, above note 8, pp. 80–179; Robert Heintsch, “The International Committee of the Red Cross and the Geneva Conventions of 1949”, in Robin Geiß, Andreas Zimmermann and Stefanie Haumer (eds), Humanizing the Laws of War: The Red Cross and the Development of International Humanitarian Law, Cambridge University Press, Cambridge, 2017, p. 27; Pictet, Jean S., “The New Conventions for the Protection of War Victims”, American Journal of International Law, Vol. 45, No. 3, 1951, pp. 464 ffCrossRefGoogle Scholar; Giovanni Mantilla, “The Origins and Evolution of the 1945 Geneva Conventions and the 1977 Additional Protocols”, in Matthew Evangelista and Nina Tannenwald (eds), Do the Geneva Conventions Matter?, Oxford University Press, Oxford, 2017, pp. 38–49.

21 Draft Rules for the Limitation of the Dangers incurred by the Civilian Population in Time of War, 19th Conference of the Red Cross, 1957; in 1965, the 20th and 21st International Conferences of the Red Cross urged the ICRC to pursue the development of IHL in this regard; the ICRC prepared drafts of two Protocols which served as a basis for discussion in the Diplomatic Conference on the Reaffirmation and Development of International Humanitarian Law Applicable in Armed Conflict, which met in Geneva in four sessions, between 1974 and 1977, with the participation of over 120 States, as well as national liberation movements, international organizations and civil society.

22 For an account of the period between 1949 and the 1977 Additional Protocols, the efforts by the ICRC, and also the role played by other actors that finally triggered the political will to negotiate the Protocols, see G. Mantilla, above note 20, pp. 52 ff; Michael Bothe, “The International Committee of the Red Cross and the Additional Protocols of 1977”, in R. Geiß, A. Zimmermann and S. Haumer (eds), above note 20, p. 57; George H. Aldrich, “Some Reflections on the Origins of the 1977 Geneva Protocols”, in Christophe Swinarski (ed.), Studies and Essays on International Humanitarian Law and Red Cross Principles in Honour of Jean Pictet, ICRC, Geneva, 1984; Bugnion, François, “Adoption of the Additional Protocols of 8 June 1977: A Milestone in the Development of International Humanitarian Law”, International Review of the Red Cross, Vol. 99, No. 2, 2017, pp. 787–90CrossRefGoogle Scholar.

23 Yves Sandoz, Christophe Swinarski and Bruno Zimmermann (eds), Commentary on the Additional Protocols, ICRC, Geneva, 1987, p. xxxiv.

24 Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on their Destruction. Opened for Signature at London, Moscow and Washington 10 April 1972 (entered into force 26 March 1975).

25 Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons Which May be Deemed to be Excessively Injurious or to Have Indiscriminate Effects, Geneva, 10 October 1980 (entered into force 2 December 1983).

26 Protocol on Non-Detectable Fragments (Protocol I), Geneva, 10 October 1980 (entered into force 2 December 1983); Protocol on Prohibitions or Restrictions on the Use of Mines, Booby-Traps and Other Devices as amended on 3 May 1996 (Protocol II as amended on 3 May 1996) (entered into force 3 December 1998); Protocol on Prohibitions or Restrictions on the Use of Incendiary Weapons (Protocol III), Geneva, 10 October 1980 (entered into force 2 December 1983); Protocol on Blinding Laser Weapons (Protocol IV), 13 October 1995 (entered into force 30 July 1998); Protocol on Explosive Remnants of War (Protocol V), 28 November 2003 (entered into force 12 November 2006).

27 Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction. Paris, 13 January 1993 (entered into force 29 April 1997).

28 Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-Personnel Mines and on their Destruction, 18 September 1997 (entered into force 1 March 1999).

29 Convention on Cluster Munitions, 30 May 2008 (entered into force 1 August 2010).

30 Treaty on the Prohibition of Nuclear Weapons, 7 July 2017 (entered into force 22 January 2021).

31 Emily Crawford, “Non-Binding Norms in the Law of Armed Conflict”, Articles of War, 3 February 2022, available at: https://lieber.westpoint.edu/non-binding-norms-law-of-armed-conflict/.

32 Mantilla, Giovanni, “Forum Isolation: Social Opprobrium and the Origins of the International Law of Internal Conflict”, International Organization, Vol. 72, No. 2, 2018, pp. 319 and 323CrossRefGoogle Scholar; Boyd van Dijk, Preparing for War, The Making of the Geneva Conventions, Oxford University Press, Oxford, 2022, describes the watering down of provisions and exclusion of certain war-time acts, such as the protection of political prisoners, starvation or the use of nuclear weapons.

33 Helen M. Kinsella and Giovanni Mantilla, “Contestation before Compliance: History, Politics, and Power in International Humanitarian Law”, International Studies Quarterly, Vol. 64, No. 3, 2020.

34 On a historical account of the making of the four Geneva Conventions from a UK perspective, see also Geoffrey Best, “Making the Geneva Conventions of 1949: The View From Whitehall”, in C. Swinarski (ed.), above note 22, pp. 67–77.

35 For a detailed analysis, see Giovanni Mantilla, “Social Pressure and the Making of Wartime Civilian Protection Rules”, European Journal of International Relations, Vol. 26, No. 2, 2020; as well as Henry Lovat, Negotiating Civil War. The Politics of International Regime Design, Cambridge University Press, Cambridge, 2020.

36 H. Lovat, ibid., p. 20.

37 Jean Pictet (ed.), Commentary on the Geneva Conventions of 12 August 1949, Vol. 4: Geneva Convention relative to the Protection of Civilian Persons in Time of War, ICRC, Geneva, 1958, p. 38.

38 Caroline Moorehead, Dunant's Dream, War Switzerland and the History of the Red Cross, Caroll & Graf, New York, 1998, p. 557.

39 Elvira Rosert, presentation in “Negotiation as a Means of Building Trust: The Example of IHL Development”, session organized by the ICRC in the context of the Centre of Competence on Humanitarian Negotiation World Summit, 1 July 2021.

40 Ibid. For a more detailed analysis of theories on why States adhere to international law in general, and IHL in particular, see Mantilla, Giovanni, “Conforming Instrumentalists: Why the USA and the United Kingdom Joined the 1949 Geneva Conventions”, European Journal of International Law, Vol. 28, No. 2, 2017CrossRefGoogle Scholar.

41 G. Best, above note 34, pp. 68–71.

42 Article (2)(g) of the Statutes of the International Red Cross and Red Crescent Movement adopted by the 25th International Conference in 1986. For the role of the ICRC and the Movement in the development of IHL, see in particular R. Geiß, A. Zimmermann and S. Haumer (eds), above note 20; F. Bugnion, above note 10, pp. 193 ff; Dörmann, Knut, “The Role of Nonstate Entities in Developing and Promoting International Humanitarian Law”, Vanderbilt Journal of Transnational Law, Vol. 51, 2018Google Scholar; Knut Dörmann and Louis Maresca, “The International Committee of the Red Cross and its Contribution to the Development of International Humanitarian Law in Specialized Instruments”, Chicago Journal of International Law, Vol. 5, No. 1, 2004, pp. 221–4; Jean-Philippe Lavoyer and Louis Maresca, “The Role of the ICRC in the Development of International Humanitarian Law”, International Negotiation, Vol. 4, No. 3, 1999, pp. 503–4; Gabriel Pablo Valladares, “El Comité internacional de la Cruz Roja (CICR) y su contribución a los últimos desarrollos del derecho internacional humanitario”, Anuário brasileiro de direito internacional, Vol. 2, No. 13, 2012; Yves Sandoz, “The International Committee of the Red Cross as Guardian of International Humanitarian Law”, Yugoslav Review of International Law, 1996, available at: www.icrc.org/en/doc/resources/documents/misc/about-the-icrc-311298.htm; Hans-Peter Gasser, “International Committee of the Red Cross (ICRC)”, Max Planck Encyclopedia of Public International Law, June 2016, para. 28, available at: https://opil.ouplaw.com/view/10.1093/law:epil/9780199231690/law-9780199231690-e310?rskey=1RM8pW&result=1&prd=MPIL; David P. Forsythe and Barbara Ann J. Rieffer-Flanagan, The International Committee of the Red Cross: A Neutral Humanitarian Actor, 2nd ed., Routledge, London and New York, 2016, pp. 38–53.

43 E. Rosert, above note 39.

44 ICRC, “Peter Maurer: ‘We Must Decide What Role we Want Human Beings to Play in Life-and-Death Decisions During Armed Conflicts’”, 12 May 2021, available at: www.icrc.org/en/document/peter-maurer-role-autonomous-weapons-armed-conflict.

45 Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Adoption of an Additional Distinctive Emblem (Protocol III), 8 December 2005 (entered into force 14 January 2007) (AP III). AP III designated the red crystal as a protective emblem equivalent to the red cross and the red crescent.

46 Protocol for the Protection of Cultural Property in the Event of Armed Conflict. The Hague, 14 May 1954 (entered into force 7 August 1956).

47 Second Protocol to the Hague Convention of 1954 for the Protection of Cultural Property in the Event of Armed Conflict. The Hague, 26 March 1999 (entered into force 9 March 2004).

48 P. Tavernier, above note 6, p. 734.

49 J.-M. Henckaerts, above note 5, p. 17.

50 S. Sivakumaran, above note 7, p. 361.

51 International Criminal Tribunal for the former Yugoslavia (ICTY), The Prosecutor v. Duško Tadić, Case No. IT-94-1-AR72, Decision (Appeals Chamber), 2 October 1995, para. 83; ICTY, Prosecutor v. Zdravko Mucić, Hazim Delić, Esad Landžo and Zejnil Delalić, Case No. IT-96-21-T, Judgment (Trial Chamber), 16 November 1998 (Čelebići case), para. 202; Jean-Marie Henckaerts and Louise Doswald-Beck (eds), “Introduction”, in Customary International Humanitarian Law, Vol. 1: Rules, Cambridge University Press, Cambridge, 2005, pp. xliv and xlviii–li, available at: https://ihl-databases.icrc.org/customary-ihl/eng/docindex/v1_rul_in; Henckaerts, Jean-Marie, “Study on Customary International Law: A Contribution to the Understanding and Respect for the Rule of Law in Armed Conflict”, International Review of the Red Cross, Vol. 87, No. 857, 2005, p. 180CrossRefGoogle Scholar; Tullio Treves, “Customary International Law”, in Max Planck Encyclopedia of Public International Law, November 2006, paras 3, 9, 38 and 85, available at: https://opil.ouplaw.com/view/10.1093/law:epil/9780199231690/law-9780199231690-e1393?rskey=IR8g8G&result=1&prd=OPIL; Robert Heinsch, “Methodological Challenges in Ascertaining Customary International Humanitarian Law: Can Customary International Law Respond to Changing Circumstances in Warfare?”, in Heike Krieger and Jonas Püschmann (eds), Law-Making and Legitimacy in International Humanitarian Law, Edward Elgar Publishing, Cheltenham and Northampton, MA, 2021.

52 S. Sivakumaran, above note 7, p. 360.

53 Recommendation II of the Intergovernmental Group of Experts for the Protection of War Victims, Geneva, 23–27 January 1995, endorsed by Resolution 1 of the 26th International Conference of the Red Cross and Red Crescent in 1995; see ICRC, “International Humanitarian Law: From Law to Action Report on the Follow-up to the International Conference for the Protection of War Victims”, available at: www.icrc.org/en/doc/resources/documents/resolution/26-international-conference-resolution-1-1995.htm.

54 Alexander, Amanda, “A Short History of International Humanitarian Law”, European Journal of International Law, Vol. 26, No. 1, 2015, p. 128CrossRefGoogle Scholar; Remarks of Lieutenant Professor William V. O'Brien in Martin P. Dupuis, John Q. Heywood and Michéle Y. F. Sarko, “The Sixth Annual American Red Cross–Washington College of Law Conference on International Humanitarian Law: A Workshop on Customary International Law and the 1977 Protocols Additional to the 1949 Geneva Conventions”, American University International Law Review, Vol. 2, No. 2, 1987, p. 511; Matheson, Michael J., “Session One: The United States Position on the Relation of Customary International Law to the 1977 Protocols Additional to the 1949 Geneva Conventions”, American University Journal of International Law and Policy, Vol. 2, 1987, p. 422Google Scholar (as cited by A. Alexander, ibid.).

55 A. Alexander, above note 54, pp. 130–1.

56 The fact that the majority of the Protocol's provisions have corresponding customary rules is demonstrated by the ICRC's Customary IHL Study. The Study was commissioned by the 26th International Conference of the Red Cross and Red Crescent, which mandated the ICRC to prepare a report on customary rules of IHL applicable in IACs and NIACs; see J.-M. Henckaerts, above note 5, p. 17.

57 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, pp. 8–10; G. Mantilla, above note 20, pp. 64–5; Y. Sandoz, C. Swinarski and B. Zimmermann (eds), above note 23, pp. 1335–6; G. Best, above note 8, pp. 343–7; G. Mantilla, above note 32, pp. 321 ff; H. Lovat, above note 35, pp. 147–58.

58 Protocol on Explosive Remnants of War, above note 26, in particular, Arts 3, 4 and 6.

59 Rome Statute of the ICC, UN Doc. A/CONF.183/9, 17 July 1998 (entered into force 1 July 2002), Art. 8.

60 ICC-ASP/9/Res.5, 10 December 2010.

61 ICC-ASP/16/Res.4, 14 December 2017.

62 ICC-ASP/18/Res.5, 6 December 2019.

63 On the ICTY and ICTR, see Robert Heinsch, “Judicial ‘Lawmaking’ in the Jurisprudence of the ICTY and ICTR in Relation to Protecting Civilians From Mass Violence: How Can Judge-Made Law be Brought into Coherence with the Doctrine of the Formal Sources of International Law?, in Philipp Ambach, Frédéric Bostedt, Grant Dawson and Steve Kostas (eds), The Protection of Non-Combatants During Armed Conflict and Safeguarding the Rights of Victims in Post-Conflict Society: Essays in Honour of the Life and Work of Joakim Dungel, Brill Nijhoff, Leiden and Boston, MA, 2015. On other international and regional judicial bodies and IHL, see, e.g., Juana María Ibáñez Rivas, “El derecho internacional humanitario en la jurisprudencia de la Corte Interamericana de Derechos Humanos”, Revista Derecho del Estado, Vol. 36, 2016; Linos-Alexandre Sicilianos, “L'articulation entre droit international humanitaire et droits de l'homme dans la jurisprudence de la Cour européenne des droits de l'homme”, Revue suisse de droit international et de droit européen, Vol. 27, No. 1, 2017; Olivier de Frouville and Olivia Martelly, “La juridictionnalisation du droit des conflits armés : les tribunaux internationaux mixtes”, in Vincent Chetail (ed.), Permanence et mutation du droit des conflits armés, Bruylant, Brussels, 2013; Vincent Chetail, “The Contribution of the International Court of Justice to International Humanitarian Law”, International Review of the Red Cross, No. 850, 2003; Christopher Greenwood, “The International Court of Justice and International Humanitarian Law”, in Shielding Humanity: Essays in International Law in Honour of Judge Abdul G. Koroma, Brill/Nijhoff, Leiden/Boston, 2015; Shane Darcy, “A Subtle yet Significant Influence: Judicial Decisions and the Development of International Humanitarian Law”, in H. Krieger and J. Püschmann (eds), above note 51; Jérôme de Hemptinne, “L’évolution des fonctions du juge pénal international et le développement du droit international humanitaire”, in Nico Krisch, Mario Prost and Anne van Aaken (eds), European Society of International Law Conference Paper Series No. 10/2013; Robert Cryer, “The Relationship of International Humanitarian Law and War Crimes: International Criminal Tribunals and their Statutes”, in Caroline Harvey, James Summers and Nigel D. White (eds), Contemporary Challenges to the Laws of War: Essays in Honour of Professor Peter Rowe, Cambridge University Press, Cambridge, 2014.

64 ICTY, The Prosecutor v. Duško Tadić, Case No. IT-94-1-AR72, Decision (Appeals Chamber), 2 October 1995, para. 142.

65 Eve La Haye, War Crimes in Internal Armed Conflicts, Cambridge University Press, Cambridge, 2008, p. 136.

66 Ibid.

67 Ibid., p. 174.

68 See, characteristically, ICTY, The Prosecutor v. Dragomir Milošević, Case No. IT-98-29/1-A, Judgment on Appeal (Appeal Chamber), 12 November 2009, para. 53.

69 Daniel Bethlehem, “The Methodological Framework of the Study”, in Elizabeth Wilmshurst and Susan Breau (eds), Perspectives on the ICRC Study on Customary International Humanitarian Law, Cambridge University Press, Cambridge, 2007, pp. 10–14; Marco Sassòli, “Taking Armed Groups Seriously: Ways to Improve their Compliance with International Humanitarian Law”, Journal of International Humanitarian Legal Studies, Vol. 1, 2010, pp. 17 and 21; John B. Bellinger, III and William J. Haynes II, “A US Government Response to the International Committee of the Red Cross Study Customary International Humanitarian Law”, International Review of the Red Cross, Vol. 89, No. 866, 2007, pp. 444–8; Dieter Fleck, “Die IKRK-Gewohnheitsrechtsstudie: Polarisierend oder konsensbildend?”, Humanitäres Völkerrecht: Informationsschriften, Journal of International Law of Peace and Armed Conflict, Vol. 22, No. 3, 2009.

70 Sandesh Sivakumaran, The Law of Non-International Armed Conflict, Oxford University Press, Oxford, 2012, p. 104; Aharon Barak, “International Humanitarian Law and the Israeli Supreme Court”, Israel Law Review, Vol. 47, No. 2, 2014, p. 184; Marko Milanovic and Sandesh Sivakumaran, “Assessing the Authority of the ICRC Customary IHL Study”, International Review of the Red Cross, Vol. 104, No. 2–3, 2022.

71 ICTY, The Prosecutor v. Ljube Boskoski and Johan Tarčulovski, Case No. IT-04-82-T, Judgment (Trial Chamber II), 10 July 2008, para. 205; European Court of Human Rights, Hannan v. Germany, Application No. 4871/16, Judgment (Grand Chamber), paras 80, 81 and 83; US Court of Military Commission Review, United States of America v. Ali Hamza Ahmad Suliman Al Bahlul, Case No. 820 F. Supp. 2d 1141 (M.C. 2011), No. CMCR 09-001, Judgment, 9 September 2011, available at: www.courtlistener.com/opinion/2143196/united-states-v-al-bahlul/; New Zealand Defence Force, Manual of Armed Forces Law, Vol. 4: Law of Armed Conflict, DM 69, 2nd ed., 2019, p. 3–16, para. 3.4.7 and subsequent references on various rules, available at: www.onlinelibrary.iihl.org/wp-content/uploads/2021/05/NZ-Manual-Law-of-Armed-Conflict.pdf; República de Colombia, Comando General de las Fuerzas Militares, Operational Law Manual for the Armed Forces (Manual de derecho operacional paralas fuerzas militares), MM.FF. 3-41, 2nd ed., 2015, multiple references; German Federal Ministry of Defence, Law of Armed Conflict: Manual, Joint Service Regulation (ZDv) 15/2, May 2013, p. 19, available at: www.bmvg.de/resource/blob/93610/ae27428ce99dfa6bbd8897c269e7d214/b-02-02-10-download-manual-law-of-armed-conflict-data.pdf; Danish Ministry of Defence, Military Manual on International Law Relevant to Danish Armed Forces in International Operations, 2016, p. 118 and subsequent references, available at: www.forsvaret.dk/globalassets/fko---forsvaret/dokumenter/publikationer/-military-manual-updated-2020-2.pdf; Belgium, Manuel de droit operationnel, 2016, p. 107 and subsequent references.

72 S. Sivakumaran, above note 7, p. 347.

73 Ibid., p. 362.

74 Danae Azaria, “Codification by Interpretation: The International Law Commission as an Interpreter of International Law”, European Journal of International Law, Vol. 31, 2020; for an illustration of the diverging views within the Commission over interpretation, codification and progressive development, see Report of the International Law Commission on the Work of its Sixty-Ninth Session (1 May–2 June and 3 July–4 August 2017), para. 134, available at: https://legal.un.org/ilc/reports/2017/english/chp7.pdf.

75 On the role of the judiciary in driving change in international law, see also Nico Krisch, “The Dynamics of International Law Redux”, Current Legal Problems, Vol. 74, No. 1, 2021, pp. 20–21; “Interview with Ted Meron, Judge, International Residual Mechanism for Criminal Tribunals”, International Review of the Red Cross, Vol. 104, No. 2–3, 2022.

76 ILC, reports of the Special Rapporteur (2013–2018): ILC, Report of the International Law Commission, UN Doc. A/68/10, 2013, Chapter IV, paras 29–39; ILC, Report of the International Law Commission, UN Doc. A/69/10, 2014, Chapter VII, paras 66–76; ILC, Report of the International Law Commission, UN Doc. A/70/10, 2015, Chapter VIII, paras 118–29; ILC, Report of the International Law Commission, UN Doc. A/71/10, 2016, Chapter VI, paras 64–76; ILC, Fifth Report on Subsequent Agreements and Subsequent Practice in Relation to the Interpretation of Treaties by Georg Nolte, Special Rapporteur, UN Doc. A/CN.4/715, 28 February 2018; Emily Crawford, “Interpreting the Geneva Conventions: Subsequent Practice Instead of Treaty Amendments? A Case Study of ‘Non-International Armed Conflicts’ Under Common Article 3”, in H. Krieger and J. Püschmann (eds), above note 51; Jean-Marie Henckaerts and Elvina Pothelet, “The Interpretation of IHL Treaties: Subsequent Practice and Other Salient Issues”, in H. Krieger and J. Püschmann (eds), above note 51; Irina Buga, Modification of Treaties by Subsequent Practice, Oxford University Press, Oxford, 2018; Georg Nolte (ed.), Treaties and Subsequent Practice, Oxford University Press, Oxford, 2013; Benedict Abrahamson Chigara, “Treaty-Text Loyalists’ Burden with Subsequent State Practice”, Netherlands International Law Review, Vol. 68, 2021; Julian Arato, “Subsequent Practice and Evolutive Interpretation: Techniques of Treaty Interpretation over Time and Their Diverse Consequences”, IILJ Emerging Scholars Papers, 2011; Abassali Kadkhodaei and Ehsan Shahsavari, “The Role of Subsequent Practice in the Interpretation of Constituent Treaties of International Organizations”, Public Law Studies Quarterly, Vol. 52, No. 1, 2022.

77 For further discussion on the interplay between treaty, interpretation and custom, see E. Crawford, above note 76.

78 Laurie R. Blank, “Understanding When and How Domestic Courts Apply IHL”, Case Western Reserve Journal of International Law, Vol. 44, No. 1, 2011.

79 S. Sivakumaran, above note 7, p. 384.

80 Sharon Weill, “Building Respect for IHL Through National Courts”, International Review of the Red Cross, Vol. 96, No. 895/896, 2014, p. 875.

81 Sharon Weill, The Role of National Courts in Applying International Humanitarian Law, Oxford University Press, Oxford, 2014, pp. 157 ff.

82 Eyal Benvenisti, The International Law of Occupation, 2nd ed., Oxford University Press, Oxford, 2012, pp. 320–8.

83 David Kretzmer, “The Law of Belligerent Occupation in the Supreme Court of Israel”, International Review of the Red Cross, Vol. 94, No. 885, 2012, p. 236; David Kretzmer and Yaël Ronen, The Occupation of Justice: The Supreme Court of Israel and the Occupied Territories, Oxford University Press, Oxford, 2021, pp. 490–4.

84 Craig Jones, The War Lawyers: The United States, Israel, and Juridical Warfare, Oxford University Press, Oxford, 2020, p. 182; Hilly Moodrick-Even Khen, “Can We Now Tell What ‘Direct Participation in Hostilities’ Is?”, Israel Law Review, Vol. 40, No. 1, 2007, pp. 233–6; Kristen E. Eichensehr, “On Target? The Israeli Supreme Court and the Expansion of Targeted Killings”, Yale Law Journal, Vol. 116, No. 8, 2007. The various reactions to the judgment are also discussed in D. Kretzmer and Y. Ronen, above note 83, p. 476.

85 Ashley Deeks, “Domestic Humanitarian Law: Developing the Law of War in Domestic Courts”, in Derek Jinks, Jackson N. Maogoto and Solon Solomon (eds), Applying International Humanitarian Law in Judicial and Quasi-Judicial Bodies: International and Domestic Aspects, Asser Press, The Hague, 2014, p. 147; Report of the Special Rapporteur on extrajudicial, summary or arbitrary executions, Philip Alston, “Study on targeted killings”, UN Doc. A/HRC/14/24/Add.6, 28 May 2010, paras 1, 7 and 12; C. Jones, above note 84, pp. 5–6 and 11.

86 See, e.g., A. Barak, above note 70, p. 187. For an example of misapplication of IHL, see Chintan Chandrachud, “International Humanitarian Law in Indian Courts: Application, Misapplication and Non-Application”, in D. Jinks et al. (eds), above note 85, p. 405.

87 Gloria Gaggioli, L'Influence mutuelle entre les droits de l'homme et le droit international humanitaire à la lumière du droit à la vie, Editions A. Pedone, Paris, 2013, p. 529; Gerd Oberleitner, “The Development of IHL by Human Rights Bodies”, in Ezequiel Heffes, Marcos D. Kotlik and Manuel J. Ventura (eds), International Humanitarian Law and Non-State Actors: Debates, Law And Practice, Asser Press, The Hague, 2020, pp. 298 ff; Lawrence Hill-Cawthorne, “Humanitarian Law, Human Rights Law and the Bifurcation of Armed Conflict”, International and Comparative Law Quarterly, Vol. 64, No. 2, 2015, pp. 304 ff; David Weissbrodt, Joseph C. Hansen and Nathaniel H. Nesbitt, “The Role of the Committee on the Rights of the Child in Interpreting and Developing International Humanitarian Law”, Harvard Human Rights Journal, Vol. 24, No. 1, 2011, pp. 127 and 139–40; Edoardo Greppi, “Diritto internazionale umanitario dei conflitti armati e diritti umani: profili di una convergenza”, La Comunità Internazionale, Vol. LI, No. 3, 1996; Robert Kolb, “‘Condotta e utilità’ e ‘mantenimento dell'ordine’: Due concetti chiave nella definizione dei rapporti tra diritto internazionale umanitario e diritti umani”, in Adriana Di Stefano (ed.), La tutela dei diritti umani e il diritto internazionale, Editoriale Scientifica, Naples, 2012; D. Kretzmer and Y. Ronen, above note 83, pp. 86–9; Hans-Joachim Heintze, “Theorien zum Verhältnis von Menschenrechten und humanitärem Völkerrecht”, Humanitäres Völkerrecht: Informationsschriften, Journal of International Law of Peace and Armed Conflict, Vol. 24, No. 1, 2011; Damien Scalia and Marie-Laurence Hebert-Dolbec, “The Intricate Relationship Between International Human Rights Law and International Humanitarian Law in the European Court for Human Rights Case Law: An Analysis of the Specific Case of Detention in Non-International Armed Conflicts”, in Drazan Djukic and Niccolò Pons (eds), The Companion to International Humanitarian Law, Brill Nijhoff, Leiden, 2018, pp. 118–22.

88 Noam Lubell, Jelena Pejic and Claire Simmons, Guidelines on Investigating Violations of International Humanitarian Law: Law, Policy, and Good Practice, ICRC and Geneva Academy, September 2019, paras 18 and 34, available at: www.icrc.org/en/document/guidelines-investigating-violations-ihl-law-policy-and-good-practice; Cordula Droege, “Elective Affinities? Human Rights and Humanitarian Law”, International Review of the Red Cross, Vol. 90, No. 871, 2008, pp. 540 ff; Michelle Lesh, “A Critical Discussion of the Second Turkel Report and How it Engages with Duty To Investigate Under International Law”, Yearbook of International Humanitarian Law, Vol. 16, 2013.

89 ICRC, Commentary on the Third Geneva Convention: Convention (III) on Prisoners of War, 2020, para. 1761.

90 See GC I, Art. 12 and GC II, Art. 12 (“Women shall be treated with all consideration due to their sex.”); GC III, Art. 14 (“Women shall be treated with all the regard due to their sex.”); GC IV, Art. 27 (“Women shall be especially protected against any attack on their honour, in particular against rape, enforced prostitution, or any form of indecent assault.”).

91 Judith Gardam, “A Feminist Analysis of Certain Aspects of International Humanitarian Law”, Australian Year Book of International Law, Vol. 12, 1992, pp. 266 and 277; Judith Gardam and Hilary Charlesworth. “Protection of Women in Armed Conflict”, Human Rights Quarterly, Vol. 22, No. 1, 2000, pp. 149 ff; Catherine O'Rourke, Women's Rights in Armed Conflict under International Law, Cambridge University Press, Cambridge, 2020, pp. 36–43; Orly Maya Stern, Gender, Conflict and International Humanitarian Law: A Critique of the “Principle of Distinction”, Routledge Studies in Humanitarian Action, Routledge, Abingdon, 2019, pp. 100 and 103.

92 C. O'Rourke, above note 91.

93 ICRC, above note 89, paras 587, 613 and 1761.

94 For more on this topic, see Janet E. Lord, “Persons with Disabilities in International Humanitarian Law – Paternalism, Protectionism or Rights?”, in Michael Gill and Cathy J. Schlund-Vials (eds), Disability, Human Rights and the Limits of Humanitarianism, Routledge, London and New York, 2016.

95 ICRC, 2016 Commentary on GC I, commentary on common Article 3, para. 553. Both the 2016 Commentary, as well as the original ICRC 1952 Commentary on GC I, are available at: https://ihl-databases.icrc.org/ihl/full/GCI-commentary. For a description of the concepts of “disability” and “persons with disabilities” in the CRPD, see Convention on the Rights of Persons with Disabilities, New York, 13 December 2006 (entered into force on 3 May 2008), Preambular para. (e) and Art. 1(2).

96 Alice Priddy, Disability and Armed Conflict, Academy Briefing No. 14, The Geneva Academy of International Humanitarian Law and Human Rights, Geneva, April 2019, available at: www.geneva-academy.ch/joomlatools-files/docman-files/Academy%20Briefing%2014-interactif.pdf; ICRC, How Law Protects Persons with Disabilities in Armed Conflict, 13 December 2017, available at: www.icrc.org/en/document/how-law-protects-persons-disabilities-armed-conflict; Report of the Special Rapporteur on the Rights of Persons with Disabilities, Gerard Quinn, UN Doc. A/76/146, 19 July 2021; Report of the Special Rapporteur on the Rights of Persons with Disabilities, Gerard Quinn, UN Doc. A/77/203, 20 July 2022.

97 José Luis Rodríguez-Villasante y Prieto, “Introducción a un ‘soft law’ humanitario: Principales aportaciones de los manuales doctrinales internacionales y otros documentos institucionales y académicos al derecho internacional humanitario”, Revista española de derecho militar, Vol. 108, 2017; P. Tavernier, above note 6, pp. 738–41.

98 S. Sivakumaran, above note 7, pp. 358, 360–1 and 391. See also “Interview with Eirini Giorgou, Legal Adviser, ICRC Arms and Conduct of Hostilities Unit”, International Review of the Red Cross, Vol. 104, No. 2–3, 2022.

99 See P. Tavernier, above note 6, p. 738; Wouter G. Werner, “The Law at Hand: Paratext in Manuals on International Humanitarian Law”, in H. Krieger and J. Püschmann (eds), above note 51.

100 See S. Sivakumaran, above note 7, p. 366.

101 The Laws of War on Land, Oxford, 9 September 1880 (Oxford Manual).

102 Ibid., Preface. See also E. Crawford, above note 31.

103 Heinz Marcus Hanke, “The 1923 Hague Rules of Air Warfare: A Contribution to the Development of International Law Protecting Civilians From Air Attack”, International Review of the Red Cross, Vol. 33, No. 292, 1993, pp. 36 and 39.

104 San Remo Manual on International Law Applicable to Armed Conflicts at Sea, 12 June 1994.

105 Wolff Heintschel von Heinegg, “Current State of the Law of Naval Warfare: A Fresh Look at the San Remo Manual”, International Law Studies, Vol. 82, pp. 270 and 288; see also Louise Doswald-Beck, “The San Remo Manual on International Law Applicable to Armed Conflicts at Sea”, American Journal of International Law, Vol. 89, No. 1, 1995, p. 193; William H. Boothby, The Law of Targeting, Oxford University Press, Oxford, 2012, p. 313.

106 UN General Assembly, Basic Principles and Guidelines on the Right to a Remedy and Reparation for Victims of Gross Violations of International Human Rights Law and Serious Violations of International Humanitarian Law, Resolution 60/147, UN Doc. A/RES/60/147, 16 December 2005.

107 UN Office for the Coordination of Humanitarian Affairs, Guiding Principles on Internal Displacement, 2nd ed., 2004, available at: www.internal-displacement.org/publications/ocha-guiding-principles-on-internal-displacement.

108 Global Protection Cluster, Fact Sheet on the Guiding Principles on Internal Displacement, available at: www.globalprotectioncluster.org/gp20/fact-sheet-on-the-guiding-principles-on-internal-displacement/; African Union Convention for the Protection and Assistance of Internally Displaced Persons in Africa (Kampala Convention), 23 October 2009 (entered into force 6 December 2012).

109 Montreux Document on Pertinent International Legal Obligations and Good Practices for States Related to Operations of Private Military and Security Companies During Armed Conflict, UN Doc. A/63/467–S/2008/636, 17 September 2008.

110 See International Institute of Humanitarian Law, The Copenhagen Process on The Handling of Detainees In International Military Operations: Principles And Guidelines, available at: https://iihl.org/wp-content/uploads/2018/04/Copenhagen-Process-Principles-and-Guidelines.pdf.

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

112 See P. Tavernier, above note 6, p. 740.

113 E. Crawford, above note 31. See also Martin Zwanenburg, “Keeping Camouflage out of the Classroom: The Safe Schools Declaration and the Guidelines for Protecting Schools and Universities from Military Use During Armed Conflict”, Journal of Conflict and Security Law, Vol. 26, No. 2, 2021.

114 Global Coalition to Protect Education from Attack (GCPEA), Safe Schools Declaration and Guidelines on Military Use, available at: https://ssd.protectingeducation.org/safe-schools-declaration-and-guidelines-on-military-use/.

115 Emanuela-Chiara Gillard, “Seventy Years of the Geneva Conventions: What of the Future?”, Chatham House, 24 March 2020, p. 12, available at: www.chathamhouse.org/2020/03/seventy-years-geneva-conventions. See also Robin Geiss and Anni Pues, “International Manuals in International Humanitarian Law: A Rejoinder to Wouter G. Werner”, in H. Krieger and J. Püschmann (eds), above note 51.

116 N. Krisch, above note 75, p. 21.

117 A form of informal lawmaking in which governments closely rely on academics is described in David Hughes and Yahli Shereshevsky, “State–Academic Law Making”, Harvard International Law Journal, Vol. 64, 2022, forthcoming.

118 S. Sivakumaran, above note 7, pp. 387–91.

119 N. Krisch, above note 75, p. 19.

120 Ibid, p. 11.

121 See, e.g., S. Sivakumaran, above note 7, on the role of so-called “state-empowered entities” and of the “community of international lawyers” in the development of the law; María Teresa Comellas Aguirrezábal, “La contribución del Consejo de Seguridad de las Naciones Unidas a la aplicación y al desarrollo normativo del derecho internacional humanitario”, Revista española de derecho militar, Vol. 85, 2005; Paul Tavernier, “La contribution du Conseil de Sécurité des Nations Unies à l’élaboration des normes du droit international humanitaire : quelques observations”, in Stéphane Doumbé-Billé and Jean-Marc Thouvenin (eds), Mélanges en l'honneur du Professeur Habib Slim : Ombres et lumières du droit international, A. Pedone, Paris, 2016; Yahli Shereshevsky, “Back in the Game: International Humanitarian Lawmaking by States”, Berkeley Journal of International Law, Vol. 37, No. 1, 2019.

122 Eyal Benvenisti and Doreen Lustig, “Monopolizing War: Codifying the Laws of War to Reassert Governmental Authority, 1856–1874”, European Journal of International Law, Vol. 31, No. 1, 2020, p. 129.

123 Ibid., pp. 139–40.

124 Ibid., p. 141.

125 Ibid., p. 169.

126 Heike Krieger and Jonas Püschmann, “A Legitimacy Crisis of International Humanitarian Law?”, in H. Krieger and J. Püschmann (eds), above note 51; William H. Boothby, “Direct Participation in Hostilities – A Discussion of the ICRC Interpretive Guidance”, Journal of International Humanitarian Legal Studies, Vol. 1, No. 1, 2010, pp. 144–5; Anton O. Petrov, Experts Laws of War: Restating and Making Law in Expert Processes, Edward Elgar Publishing, Cheltenham and Northampton, MA, 2020, pp. 20–1; Iain Scobbie, “The Approach to Customary International Law in the Study”, in E. Wilmshurst and S. Breau (eds), above note 69, pp. 16–21; D. Bethlehem, above note 69, p. 4; J. Bellinger and W. J. Haynes, above note 69; Charles Pede and Peter Hayden, “The Eighteenth Gap: Preserving the Commander's Legal Maneuver Space on ‘Battlefield Next’”, Military Review, March–April, 2021, pp. 7–8, available at: www.armyupress.army.mil/Portals/7/military-review/Archives/English/MA-21/Pede-The-18th-Gap-3.pdf.

127 C. Pede and P. Hayden, ibid.; Paul Ney, “Remarks at the Israel Defense Forces 3rd International Conference on the Law of Armed Conflict”, Just Security, 28 May 2019, available at: www.justsecurity.org/64313/remarks-by-defense-dept-general-counsel-paul-c-ney-jr-on-the-law-of-war/; Thomas Ayres, “The Use of Explosives in Cities: A Grim but Lawful Reality of War”, Joint Force Quarterly, Vol. 87, 2017, p. 26; Y. Shereshevsky, above note 121, describes the move by States to take back control over lawmaking in opposition to non-State actors, including through “unilateral” initiatives.

128 Michael N. Schmitt, “Normative Architecture and Applied International Humanitarian Law”, International Review of the Red Cross, Vol. 104, No. 2–3, 2022.

129 O. M. Stern, above note 91, p. 86; E. Crawford, above note 31; Hilary Charlesworth, Christine Chinkin and Shelley Wright, “Feminist Approaches to International Law”, American Journal of International Law, Vol. 85, No. 4, 1991, pp. 616 and 621 ff; Jasminka Kalajdic, “Rape, Representation, and Rights: Permeating International Law with the Voices of Women”, Queen's Law Journal, Vol. 21, No. 2, 1996, pp. 474 and 491; A. Priddy, above note 96, pp. 11–17; J. E. Lord, above note 94; see also Bhupinder S. Chimni, “Third World Approaches to International Law: A Manifesto”, International Community Law Review, Vol. 8, 2006, pp. 3 ff.

130 See F. Bugnion, above note 10; Claude Emanuelli, International Humanitarian Law, Bruylant, Brussels, 2009; A. Alexander, above note 54; K. Dörmann and L. Maresca, above note 42; and Kathleen Lawand and Isabel Robinson, “Development of Treaties Limiting or Prohibiting the Use of Certain Weapons: The Role of the International Committee of the Red Cross”, in R. Geiß, A. Zimmermann and S. Haumer (eds), above note 20.

131 A. Alexander, above note 54, p. 136; see also Ezequiel Heffes and Marcos D. Kotlik, “How Focusing on Non-State Actors Can Change the IHL Narrative”, OpinioJuris, 3 November 2020, available at: https://opiniojuris.org/2020/11/03/how-focusing-on-non-state-actors-can-change-the-ihl-narrative/.

132 S. Sivakumaran, above note 7, p. 393.

133 See Louise Arimatsu, “Transformative Disarmament: Crafting a Roadmap for Peace”, International Law Studies, Vol. 97, 2021; Federica du Pasquier, “Gender Diversity Dynamics in Humanitarian Negotiations: The International Committee of the Red Cross as a Case Study on the Frontlines of Armed Conflict”, Harvard Humanitarian Initiative, Humanitarian Negotiation Working Paper Series No. 1, November 2016, available at: https://hhi.harvard.edu/files/humanitarianinitiative/files/atha_gender_diversity_dynamics_in_humanitarian_negotiations.pdf?m=1610041180.

134 See Renata Dalaqua, Kjølv Egeland and Torbjørn G. Hugo, Still Behind the Curve: Gender Balance in Arms Control, Non-Proliferation and Disarmament Diplomacy, UNIDIR, 2019, available at: https://unidir.org/sites/default/files/2019-10/Still%20behind%20the%20curve.pdf.

135 Norwegian People's Aid, Patterns of Participation in Multilateral Disarmament Forums, 2020, p. 8, available at: www.npaid.org/publications/patterns-of-participation-in-multilateral-disarmament-forums.

136 Ibid., p. 9.

137 On international criminal law specifically, see William I. Pons, Janet E. Lord and Michael Ashley Stein, “Disability, Human Rights Violations, and Crimes Against Humanity”, American Journal of International Law, Vol. 116, No. 1, 2022.

138 UN, Charter on Inclusion of Persons with Disabilities in Humanitarian Action, 2016, available at: http://humanitariandisabilitycharter.org/.

139 ICRC and International Federation of Red Cross and Red Crescent Societies, “Inclusion of Persons with Disabilities in Humanitarian and Development Action”, pledge adopted at the 33rd International Conference, 2019, available at: https://rcrcconference.org/pledge/inclusion-of-persons-with-disabilities-in-humanitarian-and-development-action/; Council of Delegates of the International Red Cross and Red Crescent Movement, “Promoting Disability Inclusion in the International Red Cross and Red Crescent Movement”, Resolution, Sydney, Australia, 17–18 November 2018, available at: www.icrc.org/en/doc/assets/files/red-cross-crescent-movement/council-delegates-2013/cod13-r9--people-with-disabilities-adopted-eng.pdf.

140 E. Crawford, above note 31; for similar criticism voiced with regard to expert manuals, see A. O. Petrov, above note 126, p. 227.

141 See E.-C. Gillard, above note 115, p. 14; for the ILC draft conclusions on the identification of customary international law, see ILC, Report of the International Law Commission on the Work of its Sixty-Eighth Session, UN Doc. A/71/10, 2016, Conclusion 4(3) and para. 8 commentary to Conclusion 4, available at: https://documents-dds-ny.un.org/doc/UNDOC/GEN/G16/184/25/PDF/G1618425.pdf?OpenElement.

142 E. Heffes and M. Kotlik, above note 131.

143 Ibid; Ezequiel Heffes, “Hacia un mayor respeto del derecho internacional humanitario: utilidad, contenido y regulación de los acuerdos especiales en conflictos armados no internacionales”, Anuario Iberoamericano de Derecho Internacional Humanitario, Vol. 1, 2020.

144 See the recent study by René Provost, Rebel Courts: The Administration of Justice by Armed Insurgents, Oxford University Press, New York, 2021, pp. 433–44, which shows that States have pragmatically accepted the administration of justice by NSAGs to a greater degree than may appear at first sight.

145 M. Sassòli, above note 69, pp. 20–2; Annyssa Bellal and Ezequiel Heffes, “‘Yes, I Do’: Binding Armed Non-State Actors to IHL and Human Rights Norms Through Their Consent”, Human Rights and International Legal Discourse, Vol. 12, No. 1, 2018, pp. 126–7; Katharine Fortin, The Accountability of Armed Groups Under Human Rights Law, Oxford University Press, Oxford, 2017, p. 327; S. Sivakumaran, above note 70, p. 565; O. M. Stern, above note 91, p. 226; Katharine Fortin, “How to Cope with Diversity While Preserving Unity in Customary International Law? Some Insights From International Humanitarian Law”, Journal of Conflict and Security Law, Vol. 23, No. 3, 2018; Hyeran Jo, “Law-Making Participation by Non-State Armed Groups: The Prerequisite of Laws Legitimacy?, in H. Krieger and J. Püschmann (eds), above note 51; Lizaveta Tarasevich, “Participation of Non-State Armed Groups in the Formation of Customary International Humanitarian Law: Arising Challenges and Possible Solutions”, Humanitäres Völkerrecht: Informationsschriften, Journal of International Law of Peace and Armed Conflict, Vol. 3, No. 1–2, 2020.

146 ICTY, The Prosecutor v. Duško Tadić, Case No. IT-94-1-AR72, Decision (Appeals Chamber), 2 October 1995, paras 102–8.

147 K. Fortin, “How to Cope with Diversity”, above note 145, p. 349; Ezequiel Heffes, “Non-State Actors Engaging Non-State Actors: The Experience of Geneva Call in NIACs”, in E. Heffes, M. D. Kotlik and M. J. Ventura (eds), above note 87.

148 M. Sassòli, above note 69, p. 21; A. Bellal and E. Heffes, above note 145, p. 126; Marco Sassòli, “How Will International Humanitarian Law Develop in the Future?”, International Review of the Red Cross, Vol. 104, No. 2–3, 2022.

149 Anthea Roberts and Sandesh Sivakumaran, “Lawmaking by Nonstate Actors: Engaging Armed Groups in the Creation of International Humanitarian Law”, Yale Journal of International Law, Vol. 37, No. 1, 2012, pp. 141–51.

150 See, for instance, K. Fortin, “How to Cope with Diversity”, above note 145, pp. 350–4.

151 M. Sassòli, above note 69, p. 21; A. Bellal and E. Heffes, above note 145, p. 126; K. Fortin, above note 145, pp. 356–7.

152 Though Sivakumaran, for instance, has called for a new type of instrument binding armed groups “in all situations”, which could be drafted by States and NSAGs together; S. Sivakumaran, above note 70, p. 565.

153 K. Lawand and I. Robinson, above note 130, pp. 158 and 179–80.

154 For a comprehensive history, see Louis Maresca and Stuart Maslen, The Banning of Anti-Personnel Landmines: The Legal Contribution of the International Committee of the Red Cross 1955–1956, Cambridge University Press, Cambridge, 2000.

155 Helen Durham and Eirini Giorgou, “International Humanitarian Law and the Universality of the Geneva Conventions”, in V. Buonomo, D. Fernandez Puyana, M. Levrak, C. M. Marenghi and S. Saldi (eds), Enhancing Multilateralism and Peace, Lateran University Press, Rome, 2022, forthcoming.

156 See, for instance, the Second Protocol to the Hague Convention of 1954 for the Protection of Cultural Property in the Event of Armed Conflict, above note 47; the Optional Protocol to the Convention on the Rights of the Child on the involvement of children in armed conflict, 25 May 2000 (entered into force 12 February 2002); and AP III to the Geneva Conventions.

157 See ICRC, International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, Report submitted to the 32nd International Conference of the Red Cross and Red Crescent, 8–10 December 2015, p. 53, available at: www.icrc.org/en/document/international-humanitarian-law-and-challenges-contemporary-armed-conflicts.

158 S. Sivakumaran, above note 70, pp. 513 ff; Laura Inigo Alvarez, Towards a Regime of Responsibility of Armed Groups in International Law, Intersentia, Cambridge, 2020, p. 158; Gordon Brown and Shaheed Fatima, “Need for Change to Protect Children in Armed Conflict”, Just Security, 2 November 2018, available at: www.justsecurity.org/61335/gordon-brown-shaheed-fatima-change-protect-children-armed-conflict/; Ruth Abril Stoffels, “Legal Regulation of Humanitarian Assistance in Armed Conflict: Achievements and Gaps”, International Review of the Red Cross, Vol. 86, No. 855, 2004, p. 520; Michael Bothe, Carl Bruch, Jordan Diamond and David Jensen, “International Law Protecting the Environment During Armed Conflict: Gaps and Opportunities”, International Review of the Red Cross, Vol. 92, No. 879, 2010, pp. 575 ff; Eric Prokosch, “The Development of the Convention on Conventional Weapons 1971–2003”, Article 36, Guest Research Briefing, November 2021, pp. 8–9, available at: https://article36.org/wp-content/uploads/2021/12/The-Development-of-the-CCW.pdf?mc_phishing_protection_id=28048-c7anv7f0s0v91iu3cerg, on the unfinished agenda of the CCW; Brad Smith, “The Need for a Digital Geneva Convention”, 14 February 2017, available at: https://blogs.microsoft.com/on-the-issues/2017/02/14/need-digital-geneva-convention/; O. M. Stern, above note 91. Robert Heinsch, “Der Wandel des Kriegsbegriffs: Brauchen wir eine Revision des humanitären Völkerrechts?”, Humanitäres Völkerrecht: Informationsschriften, Journal of International Law of Peace and Armed Conflict, Vol. 23, No. 3, 2010; P. Tavernier, above note 6, pp. 741–7; Karine Bannelier-Christakis, “Is the Principle of Distinction Still Relevant in Cyberwarfare?”, in Nicholas Tsagourias and Russell Buchan (eds), Research Handbook on International Law and Cyberspace, Edward Elgar Publishing, Cheltenham and Northampton, MA, 2015; Giacomo Biggio, “International Humanitarian Law and the Protection of the Civilian Population in Cyberspace: Towards a Human Dignity-Oriented Interpretation of the Notion of Cyber Attack Under Article 49 of Additional Protocol I”, Military Law and Law of War Review, Vol. 59, No. 1, 2021; Matilda Arvidsson, “Targeting, Gender, and International Posthumanitarian Law and Practice: Framing the Question of the Human in International Humanitarian Law”, Australian Feminist Law Journal, Vol. 44, No. 1, 2018; Judith Gardam, “The Silences in the Rules that Regulate Women During Times of Armed Conflict”, in Fionnuala Ní Aoláin, Naomi Cahn, Dina Francesca Haynes and Nahla Valji (eds), The Oxford Handbook of Gender and Conflict, Oxford University Press, Oxford, 2018; Ezequiel Heffes, “The International Responsibility of Non-State Armed Groups: In Search of the Applicable Rules”, Goettingen Journal of International Law, Vol. 8, No. 1, 2017; Kubo Macak, “A Needle in a Haystack? Locating the Legal Basis for Detention in Non-International Armed Conflict”, Israel Yearbook on Human Rights, Vol. 45, 2015; Gregory Rose, “Management of Detention of Non-State Actors Engaged in Hostilities: Recommendations for Future Law”, in Gregory Rose and Bruce Oswald, Detention of Non-State Actors Engaged In Hostilities: The Future Law, Brill Nijhoff, Leiden and Boston, 2016; Sandesh Sivakumaran, “Re-Envisaging the International Law of Internal Armed Conflict”, European Journal of International Law, Vol. 22, No. 1, 2011.

159 ICRC, Strengthening Legal Protection for Victims of Armed Conflicts, Report submitted to the 31st International Conference of the Red Cross and Red Crescent, 28 November–1 December 2011, available at: www.icrc.org/en/doc/assets/files/red-cross-crescent-movement/31st-international-conference/31-int-conference-5-1-1-report-strength-ihl-en.pdf. The areas identified were: the protection of persons deprived of liberty in NIAC; the protection of the natural environment; the protection of internally displaced persons; and international mechanisms to monitor compliance with international humanitarian law and reparation for victims of violations.

160 See ICRC, Strengthening International Humanitarian Law Project, available at: www.icrc.org/en/war-and-law/strengthening-ihl; Tilman Rodenhäuser, “Strengthening IHL Protecting Persons Deprived of Their Liberty: Main Aspects of the Consultations and Discussions Since 2011”, International Review of the Red Cross, Vol. 98, No. 903, 2016; Jelena Pejic, “Strengthening Compliance with IHL: The ICRC–Swiss Initiative”, International Review of the Red Cross, Vol. 98, No. 1, 2016.

161 Phil Twyford, “Government Commits to International Effort to Ban and Regulate Killer Robots”, New Zealand Government Press Release, 30 November 2021, available at: www.beehive.govt.nz/release/government-commits-international-effort-ban-and-regulate-killer-robots; UN Secretary-General, “Secretary-General's Message to the Sixth Review Conference of High Contracting Parties to the Convention on Certain Conventional Weapons”, 13 December 2021, available at: www.un.org/sg/en/content/sg/statement/2021-12-13/secretary-generals-message-the-sixth-review-conference-of-high-contracting-parties-the-convention-certain-conventional-weapons-scroll-down-for-french-version; Human Rights Watch, “Stopping Killer Robots: Country Positions on Banning Fully Autonomous Weapons and Retaining Human Control”, 10 August 2020, available at: www.hrw.org/report/2020/08/10/stopping-killer-robots/country-positions-banning-fully-autonomous-weapons-and; Janos Kramar, “Autonomous Weapons Open Letter: AI & Robotics Researchers”, Future of Life Institute, 9 February 2016, available at: https://futureoflife.org/2016/02/09/open-letter-autonomous-weapons-ai-robotics/?cn-reloaded=1, announced at the International Joint Conference on Artificial Intelligence on 28 July 2015; Frank Sauer, “Autonomy in Weapons Systems: Playing Catch Up with Technology”, Humanitarian Law & Policy, 29 September 2021, available at: https://blogs.icrc.org/law-and-policy/2021/09/29/autonomous-weapons-systems-technology/; ICRC, “ICRC Position on Autonomous Weapon Systems”, 12 May 2021, available at: www.icrc.org/en/document/icrc-position-autonomous-weapon-systems.

162 E.-C. Gillard, above note 115, p. 10.

163 O. M. Stern, above note 91, p. 225.

164 Susan Marks, “Backlash: The Undeclared War against Human Rights”, European Human Rights Law Review, Vol. 4, 2014; Martti Koskenniemi, “International Law and the Backlash Against Globalization”, Lecture at IHEID (Graduate Institute of International and Development Studies), 3 March 2020; Human Rights Council, Report of the Working Group on the Issue of Discrimination against Women in Law and in Practice, UN Doc. A/HRC/38/46, 14 May 2018, para. 14; Australian National University, “Navigating the Backlash against Global Law and Institutions”, available at: https://law.anu.edu.au/navigating-backlash-against-global-law-and-institutions; Jeremy Farrall, Jolyon Ford and Imogen Saunders, “The Backlash against International Law: Australian Perspectives”, Australian Year Book of International Law Online, Vol. 38, No. 1, 2020; Mikael Rask Madsen, Pola Cebulak and Micha Wiebusch, “Backlash against International Courts: Explaining the Forms and Patterns of Resistance to International Courts”, International Journal of Law in Context, Vol. 14, 2018; Karen J. Alter, “The Contested Authority and Legitimacy of International Law: The State Strikes Back”, iCourts Working Paper Series No. 134, 2018, available at: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3204382; Frederick V. Perry, “The Assault on International Law: Populism and Entropy on the March”, Syracuse Journal of International Law and Commerce, Vol. 46, No. 1, 2018.

165 O. M. Stern, above note 91, p. 225.

166 See E. Crawford, above note 31.

167 A term coined by Sunstein, Cass, “Social Norms and Social Roles”, Columbia Law Review, Vol. 96, No. 4, 1996CrossRefGoogle Scholar. See also Stephan, Paul B., “The Crisis in International Law and the Path Forward for International Humanitarian Law”, International Review of the Red Cross, Vol. 104, No. 2–3, 2022Google Scholar.

168 H. Lovat, above note 35.

169 G. Mantilla, above note 32, p. 323.

170 See, e.g., E. Prokosch, above note 158, p. 7, on the varying role of evidence in treaty negotiations.

171 S. Sivakumaran, above note 70, p. 565.

172 Antonio Cassese (ed.), Realizing Utopia, The Future of International Law, Oxford University Press, Oxford, 2012, p. 525.