1 For a full list, see: www.un.org/counterterrorism/international-legal-instruments (all internet references were accessed in August 2021).

2 See, for example, O'Donnell, Daniel, “International Treaties against Terrorism and the Use of Terrorism during Armed Conflict and by Armed Forces”, International Review of the Red Cross, Vol. 88, No. 864, 2006CrossRefGoogle Scholar; Frias, Alejandro Sanchez, “Bringing Terrorists to Justice in the Context of Armed Conflict: Interaction between International Humanitarian Law and the UN Conventions against Terrorism’, Israel Law Review, Vol. 53, No. 1, 2020Google Scholar; Ben Saul, “Terrorism, Counter-Terrorism, and International Humanitarian Law”, in Ben Saul and Dapo Akande (eds), The Oxford Guide to International Humanitarian Law, Oxford University Press, Oxford and New York, 2020, p. 403; Andrea Bianchi and Yasmin Naqvi, International Humanitarian Law and Terrorism, Hart, Oxford, 2011.

3 Lewis, Dustin A., “‘Criminalization’ of Humanitarian Action under Counterterrorism Frameworks: Key Elements and Concerns’, Proceedings of the ASIL Annual Meeting, Vol. 112, 2018, p. 269Google Scholar.

4 See, for example, International Convention for the Suppression of the Financing of Terrorism, 2178 UNTS 107, 9 December 1999 (entered into force 10 April 2002) (Terrorist Financing Convention), Art. 2(1)(b).

5 See also Fionnuala Ní Aoláin, Report of the Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms while Countering Terrorism, UN Doc. A/75/337, 3 September 2020, para. 22 (accepting the author's submissions on some of the following points).

6 Convention on the Physical Protection of Nuclear Material, 1456 UNTS 101, 3 March 1980 (entered into force 8 February 1987) as amended by the Amendment to the Convention on the Physical Protection of Nuclear Material 1980, 8 July 2005 (entered into force 8 May 2016) (Amended Nuclear Material Convention), Art. 7(1).

7 International Convention for the Suppression of Acts of Nuclear Terrorism, 2445 UNTS 89, 13 April 2005 (entered into force 7 July 2007) (Nuclear Terrorism Convention), Art. 2(1).

8 Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation, 974 UNTS 178, 23 September 1971 (entered into force 26 January 1973) (Montreal Convention), Art. 1(e).

9 Convention on the Suppression of Unlawful Acts relating to International Civil Aviation, 10 September 2010 (entered into force 1 July 2018) (Beijing Convention), Art. 1(1)(i).

10 Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction, 1015 UNTS 163, 10 April 1972 (entered into force 26 March 1975), Art. 3 (prohibition only); Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction, 1975 UNTS 45, 3 September 1992 (entered into force 29 April 1997), Arts 1(a), 7(1)(a), 7(1) (c); Treaty on the Prohibition of Nuclear Weapons, UN Reg. No. 56487, 7 July 2017 (entered into force 22 January 2012), Art. 1(b)–(c), 5(2).

11 See, for example, Michael N. Schmitt (ed.), Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations, 2nd ed., Cambridge University Press, Cambridge, 2017, Rules 92, 100.

12 Organization of African Unity Convention on the Prevention and Combating of Terrorism, 2219 UNTS 179, 1 July 1999 (entered into force 6 December 2002) (OAU Convention), Art. 1(3)(a).

13 Rome Statute of the International Criminal Court, 2187 UNTS 3, 17 July 1998 (entered into force 1 July 2002) (Rome Statute), Art. 8(2)(b)(iv) (“widespread, long-term, and severe damage to the natural environment which would be clearly excessive” to the military advantage anticipated, reflecting the test in 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. 35(3)). Attacks on the environment are not crimes under the four 1949 Geneva Conventions, 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), or the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques, 1108 UNTS 151, 10 December 1976 (entered into force 5 October 1978).

14 Convention for the Suppression of Unlawful Seizure of Aircraft, 860 UNTS 105, 16 December 1970 (entered into force 14 October 1971) (Hague Convention), Art. 1(a).

15 Montreal Convention, Art. 1(c).

16 The latest ICTCs require States to criminalize commission, attempt, complicity, conspiracy, and organizing or directing; a few also address threats and concealment.

17 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 195 (commission, attempt, assistance, facilitating, aiding or abetting, and planning or instigating), available at: https://ihl-databases.icrc.org/customary-ihl/eng/docs/v1.

18 See, for example, Beth Van Schaack, Imagining Justice for Syria, Oxford University Press, Oxford, 2019, Ch. 7; Emma Broches and Julia Solomon-Strauss, “International Terrorism Prosecutions during Winter 2019”, Lawfare, 21 March 2019.

19 UN Counter-Terrorism Implementation Task Force (Working Group on Protecting Human Rights while Countering Terrorism), Basic Human Rights Reference Guide: Conformity of National Counter-Terrorism Legislation with International Human Rights Law, October 2014, Principles and Guidelines 3 and paras 39–44.

20 ICRC, Commentary on the First Geneva Convention: Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, 2nd ed., Geneva, 2016 (ICRC Commentary on GC I), Art. 49, para. 2846.

21 See, for example, International Convention for the Suppression of Terrorist Bombings, 2149 UNTS 256, 15 December 1997 (entered into force 23 May 2001) (Terrorist Bombings Convention), Art. 6(4).

22 ICRC Commentary on GC I, above note 20, Art. 49, para. 2866.

23 See, for example, UNSC Res. 1373, 28 September 2001, paras 1(b), 1(d) (financing); UNSC Res. 2178, 24 September 2014, paras 6(a)–(c) (foreign terrorist fighters). See also David McKeever, “International Humanitarian Law and Counter-terrorism: Fundamental Values, Conflicting Obligations”, International and Comparative Law Quarterly, Vol. 69, No. 1, 2020, p. 51.

24 Counter-Terrorism Executive Directorate (CTED), Technical Guide to the Implementation of Security Council Resolution 1373 (2001) and Other Relevant Resolutions, 2019, para. 274 (jurisdiction based on nationality and territoriality, and quasi-universal custody-based jurisdiction only if the act is an ICTC offence; para. 2(e) itself is silent on jurisdiction but requires States to “bring to justice” all offenders, which in turn requires the State to “prosecute or extradite”: UNSC Res. 1456, 20 January 2003, para. 3; UNSC Res. 1566, 8 October 2004, para. 2).

25 See above note 24 on para. 2(e).

26 ICRC Customary Law Study, above note 17, Rules 158, 161.

27 See, for example, Terrorist Bombings Convention, Art. 15(a); Terrorist Financing Convention, Art. 18(1).

28 See, for example, Terrorist Financing Convention, Art. 18(3).

29 UNSC Res. 1373, 28 September 2001, paras 2(a) (refrain from supporting terrorism), 2(b) (prevent terrorist acts), 2(c) (deny safe haven), 2(d) (prevent use of territory for terrorism), 2(g) (prevent movement of terrorists).

30 See, for example, AP I, Arts 80, 82, 83, 86, 87.

31 ICRC Commentary on GC I, above note 20, Art. 1, para. 164.

32 Ibid., paras 130–152.

33 Ibid., para. 153.

34 See Ben Saul, Defining Terrorism in International Law, Oxford University Press, Oxford, 2006, Ch. 2.

35 Especially in relation to “foreign terrorist fighters”: see UNSC Res. 2178, 24 September 2014, para. 4; UNSC Res. 2396, 21 December 2017, paras 19 (“Reaffirms that those responsible for committing or otherwise responsible for terrorist acts, and violations of international humanitarian law or violations or abuses of human rights in this context, must be held accountable”), 29–41.

36 D. McKeever, above note 23, p. 51.

37 ICRC Commentary on GC I, above note 20, Art. 49, paras 2847–2851 (discussing options for criminalizing grave breaches, from the use of ordinary offences to specific war crimes laws).

38 War crimes are not recognized under either the Syrian Penal Code, Legislative Decree No. 148, 22 June 1949; or the Military Penal Code, Legislative Decree No. 61, 27 February 1950.

39 Afghanistan Penal Code 2017, Official Gazette No. 1260, 15 May 2017 (entered into force 14 February 2018).

40 Anti-Terrorism Act, Legislative Council Decree No. 20, 27 September 2014, under the Charter of the Social Contract, 29 January 2019 (the interim constitution of the then Democratic Autonomous Regions of Afrin, Jazira and Kobane).

41 See, for example, Bahame Tom Nyanduga, Report of the Independent Expert on the Situation of Human Rights in Somalia, UN Doc. A/HRC/30/57, 29 September 2015, paras 28–32.

42 D. McKeever, above note 23, p. 51.

43 See also F. Ní Aoláin, above note 5, para. 21. On cumulative charging, see Genocide Network, Cumulative Prosecution of Foreign Terrorist Fighters for Core International Crimes and Terrorism-related Offences, May 2020.

44 See also D. McKeever, above note 23, p. 51.

45 Ibid.

46 See, for example, US Supreme Court, Holder v. Humanitarian Law Project, 561 US (2010), Nos 08-1498, 09-89, 21 June 2010 (concerning the expansive scope of the US material support for terrorism offence in 18 USC §2339A, which has an exception for medicines and religious materials but not for medical care or humanitarian relief); Norwegian Refugee Council, Principles under Pressure: The Impact of Counterterrorism Measures and Preventing/Countering Violent Extremism on Principled Humanitarian Action, 2018.

47 UK Supreme Court (UKSC), R v. Gul, [2013] UKSC 64, 23 October 2013, para. 36 (undermines rule of law, separation of powers, and legality where wide discretion is left to prosecutors as to whether lawful hostilities under IHL are criminal under domestic law).

48 See, for example, US Department of the Navy, The Commander's Handbook on the Law of Naval Operations, 2007, para. 5.4.1.1 (“cannot be prosecuted for their lawful military actions”).

49 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), Arts 64–67.

50 AP II, Art. 6(5).

51 ICRC, International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, Geneva, 2019, p. 58 (ICRC 2019 Challenges Report). See also F. Ní Aoláin, above note 5, para. 26; ICRC, Terrorism and International Law: Challenges and Responses: The Complementary Nature of Human Rights Law, International Humanitarian Law and Refugee Law, Geneva, 2002Google Scholar; Sassòli, Marco, “Terrorism and War”, Journal of International Criminal Justice, Vol. 4, No. 5, 2006, p. 970CrossRefGoogle Scholar.

52 ICRC, Commentary on the Second Geneva Convention: Convention (II) for the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of Armed Forces at Sea, 2nd ed., Geneva, 2017 (ICRC Commentary on GC II), Art. 3, para. 895. See also ICRC, The Applicability of IHL to Terrorism and Counterterrorism, Geneva, 2015; Jelena Pejic, “Armed Conflict and Terrorism”, in Ana María Salinas de Frías, Katja Samuel and Nigel D. White (eds), Counter-Terrorism: International Law and Practice, Oxford University Press, Oxford, 2012, p. 177; Tristan Ferraro, “Interaction and Overlap between Counter-Terrorism Legislation and International Humanitarian Law”, in Terrorism, Counter-Terrorism and International Humanitarian Law, Proceedings of the Bruges Colloquium, 20–21 October 2016.

53 See, generally, Saul, Ben, “Enhancing Civilian Protection by Engaging Non-State Armed Groups under International Humanitarian Law”, Journal of Conflict and Security Law, Vol. 22, No. 1, 2017Google Scholar.

54 Ibid., pp. 25–26.

55 See also F. Ní Aoláin, above note 5, para. 26 (accepting the author's position on this point).

56 GC IV, Art. 64.

57 ICRC 2019 Challenges Report, above note 51, p. 58.

58 Ibid., p. 59.

59 Sophie Haspeslagh, “The ‘Linguistic Ceasefire’: Negotiating in an Age of Proscription”, Security Dialogue, Vol. 52, No. 4, 2021.

60 ICRC, The Applicability of IHL, above note 52; J. Pejic, above note 52; ICRC, Terrorism and International Law, above note 51. See also F. Ní Aoláin, above note 5, para. 26.

61 AP II, Art. 6(5); ICRC Customary Law Study, above note 17, Rule 159.

62 ICRC, The Applicability of IHL, above note 52; J. Pejic, above note 52; ICRC, Terrorism and International Law, above note 51.

63 UN, Integrated Disarmament, Demobilization and Reintegration Standards, 2020, Module 2.11, Sec. 4.2.6.

64 Ibid. See, for example, UNSC Res. 2178, 24 September 2014, para. 4; UNSC Res. 2396, 21 December 2017, paras 18, 29–30 (“prosecution, rehabilitation, and reintegration” measures for “foreign terrorist fighters”).

65 Convention on Offences and Certain Other Acts Committed on Board Aircraft, 704 UNTS 219, 14 September 1963 (entered into force 4 December 1969) (Tokyo Convention), Art. 1(4); Hague Convention, Art. 3(2); Montreal Convention, Art. 4; Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation, 1678 UNTS 221, 10 March 1988 (entered into force 1 March 1992) (Maritime Safety Convention), Art. 2.

66 Protocol on the Suppression of Unlawful Acts of Violence at Airports Serving International Civil Aviation, 974 UNTS 177, 24 February 1988 (entered into force 6 August 1989) (Airports Protocol), Art. II.

67 Protocol for the Suppression of Unlawful Acts against the Safety of Fixed Platforms Located on the Continental Shelf, 1678 UNTS 304, 10 March 1988 (entered into force 1 March 1992) (Fixed Platforms Protocol), Art. 1(3) (fixed platforms on the continental shelf are defined as those for resource-related or economic purposes).

68 See, for example, Convention on International Civil Aviation, 15 UNTS 295, 7 December 1944 (entered into force 4 April 1947) (Chicago Convention), Art. 3, which applies the Convention only to “civil” aircraft and excludes “state aircraft” (defined to include those used for military, customs and police services).

69 Montreal Convention, Art. 1(b).

70 International Law Commission Study Group, Report on Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law, UN Doc. A/CN.4/L.682, 13 April 2006, para. 58; see also para. 111.

71 Convention on the Prevention and Punishment of Crimes against Internationally Protected Persons, including Diplomatic Agents, 1035 UNTS 167, 14 December 1973 (entered into force 20 February 1977) (Protected Persons Convention), Art. 2(1).

72 Vienna Convention on Diplomatic Relations, 500 UNTS 95, 18 April 1961 (entered into force 24 April 1964), Arts 29 and 22 respectively.

73 As where the US failed to take necessary precautions and mistakenly targeted the Chinese embassy in Belgrade in 1999: see UN Security Council, Agenda: Letter Dated 7 May 1999 from China to the Security Council President (S/1999/523), UN Doc. S/PV.4000, 8 May 1999 (China argued that a mistaken attack by NATO forces on its Yugoslav embassy violated the Protected Persons Convention, in addition to being a war crime, and the United States paid ex gratia compensation to China and voluntary humanitarian payments to victims; since payments were without admission of liability, this is not evidence, as suggested by the commentary to the ICRC Customary Law Study, above note 17, Rule 150, of a duty to compensate for IHL violations). See also A. Sanchez Frias, above note 2, p. 74 (US extradition under the Protected Persons Convention of a suspected murderer of a US diplomat in an armed conflict in Mali); US District Court for the District of Columbia, Von Dardel v. Union of Soviet Socialist Republics, 623 F Supp 246, 15 October 1985, para. 262 (US awarded damages in an alien tort claim to for the kidnapping and possible murder of the Swedish diplomat Raoul Wallenberg by Soviet forces in occupied Hungary in 1945, in contravention of a domestic statute implementing the Protected Persons Convention).

74 The Protected Persons Convention applies to State officials who are entitled to special protection from attack under international law (that is, particularly under the VCDR) at the time of the crime; as per the VCDR, a person abusing their diplomatic functions is still entitled to inviolability. It is unsettled whether personal self-defence (or defence of others) may justify interference: Eileen Denza, Diplomatic Law: Commentary on the Vienna Convention on Diplomatic Relations, 4th ed., Oxford University Press, Oxford, 2016, p. 123.

75 International Court of Justice, United States Diplomatic and Consular Staff in Tehran (United States of America v. Iran), 1980, ICJ Reports 3, paras 83–87.

76 E. Denza, above note 74, p. 123.

77 Cf. Blank, Laurie R., “The Limits of Inviolability: The Parameters for Protection of United Nations Facilities during Armed Conflict”, International Legal Studies, Vol. 93, No. 1, 2017, p. 62Google Scholar.

78 Under the Convention on the Privileges and Immunities of the United Nations, 1 UNTS 15, 13 February 1946 (entered into force 17 September 1946) (Convention on UN Privileges and Immunities). See UN Security Council, Summary by the Secretary-General of the Report of the UN Headquarters Board of Inquiry into Certain Incidents that Occurred in the Gaza Strip between 8 July 2014 and 26 August 2014, UN Doc. S/2015/286, 27 April 2015, Annex, para. 13; UN General Assembly and Security Council, Summary by the Secretary-General of the Report of the UN Headquarters Board of Inquiry into Certain Incidents in the Gaza Strip between 27 December 2008 and 19 January 2009, UN Doc. A/63/855–S/2009/250, 15 May 2009, para. 16.

79 UN General Assembly and Security Council, above note 78, para. 16.

80 Ibid., para. 92.

81 See, for example, Eritrea-Ethiopia Claims Commission, Partial Award: Diplomatic Claim – Eritrea's Claim 20, XXVI RIAA 381, 19 December 2005, paras 45–46.

82 Convention on UN Privileges and Immunities, Art. 5(19); Convention on Privileges and Immunities of the Specialized Agencies, 33 UNTS 261, 21 November 1947 (entered into force 2 December 1948), Art. 6(21).

83 GC IV, Arts 34, 146–147.

84 International Convention against the Taking of Hostages, 1316 UNTS 205, 17 December 1979 (entered into force 3 June 1983) (Hostages Convention), Art. 12.

85 Specifically, where a hostage is not (1) a protected person under GC IV Article 4, including nationals of the State party, a co-belligerent State or a neutral State, or (2) within the expanded categories protected by AP I Article 85(2), including prisoners of war, other captured persons who took part in hostilities, stateless persons and refugees, and the wounded, sick and shipwrecked of the other party.

86 Common Art. 3(1)(b); AP II, Art. 4(2)(c); Rome Statute, Art. 8(2)(c)(iii) (NIAC); ICRC Customary Law Study, above note 17, Rule 96.

87 Verwey, Wil, “The International Hostages Convention and National Liberation Movements”, American Journal of International Law, Vol. 75, No. 1 1981, p. 85CrossRefGoogle Scholar.

88 See, generally, Ibid.; Joseph Lambert, Terrorism and Hostages in International Law: A Commentary on the Hostages Convention 1979, Grotius, Cambridge, 1990, pp. 266–273.

89 Terrorist Financing Convention, Art. 2(1)(b).

90 Italian Court of Cassation (Penal Section), Bouyahia Maher Ben Abdelaziz et al., No. 1072, 17 January 2007.

91 Terrorist Financing Convention, Arts 2(1)(a) and 2(1)(b) respectively.

92 Terrorist Bombings Convention, Art. 19(2); Nuclear Terrorism Convention, Art. 4(2); Amended Nuclear Material Convention, Art. 2(4)(b); Hague Convention (as amended by the Protocol Supplementary to the Convention for the Suppression of Unlawful Seizure of Aircraft, Beijing, 10 September 2010 (entered into force 1 January 2018)), Art. 3bis; Maritime Safety Convention, as amended by the Protocol to the Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation, 14 October 2005 (entered into force 28 July 2010) (Maritime Safety Protocol), Art. 2bis (2); Beijing Convention, Art. 6(2).

93 As under the Canadian Criminal Code, Sec. 83.01(1): see Supreme Court of Canada, R v. Khawaja, [2012] 3 SCR 555, 14 December 2012 (“since the armed conflict exception functions as a defence, the accused must raise it and make a prima facie case that it applies”).

94 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), Art. 4(A)(1).

95 Ibid., Art. 4(A)(2); AP I, Art. 43(1).

96 AP I, Art. 43(3).

97 Ibid., Art. 44(3).

98 Ibid., Art. 1(4).

99 GC III, Art 4(A)(6). Such persons are neither regular nor irregular forces under GC III, and do not qualify as armed forces under AP I because they are neither under a command responsible to the State nor subject to an internal disciplinary system. They are, however, “belligerents” under the Hague Regulations Respecting the Laws and Customs of War on Land, annexed to Hague Convention (IV) Respecting the Laws and Customs of War on Land, USTS 539, 18 October 1907 (entered into force 26 January 1910), Art. 2.

100 Cuyckens, Hanne and Paulussen, Christophe, “The Prosecution of Foreign Fighters in Western Europe: The Difficult Relationship between Counter-Terrorism and International Humanitarian Law”, Journal of Conflict and Security Law, Vol. 24, No. 3, 2019, p. 553Google Scholar.

101 See, respectively, Zwanenburg, Marten, “Foreign Terrorist Fighters in Syria: Challenges of the Sending State”, International Legal Studies, Vol. 92, No. 1, 2016, pp. 216–217Google Scholar; Hmoud, Mahmoud, “Negotiating the Draft Comprehensive Convention on International Terrorism: Major Bones of Contention”, Journal of International Criminal Justice, Vol. 4, No. 5, 2006, p. 1036CrossRefGoogle Scholar.

102 See, for example, Witten, Samuel, “The International Convention for the Suppression of Terrorist Bombings”, American Journal of International Law, Vol. 92, No. 4, 1998, p. 780CrossRefGoogle Scholar; J. Pejic, above note 52, p. 189; D. O'Donnell, above note 2, p. 866; M. Sassòli, above note 51, p. 977; Commonwealth Secretariat, Implementation Kits for the International Counter-terrorism Conventions, 2002, p. 243; Coco, Antonio, “The Mark of Cain: The Crime of Terrorism in Times of Armed Conflict as Interpreted by the Court of Appeal of England and Wales in R v Mohammed Gul”, Journal of International Criminal Justice, Vol. 11, No. 2, 2013, p. 434CrossRefGoogle Scholar.

103 J. Pejic, above note 52, p. 189.

104 ICRC Commentary on GC II, above note 52, Art. 3, para. 552; D. O'Donnell, above note 2, p. 866; M. Sassòli, above note 51, p. 977. The ICRC Commentary on GC I, above note 20, para. 429, also refers to the “organized armed forces” of non-State parties.

105 ICRC, Commentary on the Third Geneva Convention: Convention (III) relative to the Treatment of Prisoners of War, 2nd ed., Geneva, 2020 (ICRC Commentary on GC III), Art. 3, para. 564.

106 AP II, Art. 1.

107 District Court of The Hague, Prosecutor v. Imane B et al., Judgment, 10 December 2015 (Context Case), paras 7.38, 7.40.

108 AP I, Art. 43; A. Coco, above note 102, p. 434.

109 UN General Assembly, Preliminary Working Document Submitted by France on behalf of the Group of Seven Major Industrialized Countries and the Russian Federation, UN Doc. A/AC.252/L.2, 11 February 1997, Art. 3(1).

110 Carlos Díaz-Paniagua, Negotiating Terrorism: The Negotiation Dynamics of Four UN Counter-Terrorism Treaties, 1997–2005, City University of New York, 2008, pp. 317, 323.

111 See, for example, the US understandings to the ICTCs indicating, influenced by AP II, that the term “armed conflict” does not include internal disturbances and tensions such as riots, isolated and sporadic acts of violence, and other acts of a similar nature: Suppression of Terrorist Bombings Implementation Act, 2002, in 18 USC §2332f(e)(11).

112 District Court of The Hague, Context Case, above note 107, para. 7.40.

113 US President, letter of transmittal of the Terrorist Bombings Convention to the US Senate, 8 September 1999, IX–X (emphasis added); see, similarly, US President, message transmitting Protocols of 2005 to the Convention concerning Safety of Maritime Navigation and to the Protocol concerning Safety of Fixed Platforms on the Continental Shelf, 17 February 2006. Cf. the contradicting statement of William Taft IV, US State Department Legal Adviser, on anti-terrorism conventions to the US Senate, 27 November 2001 (only regular State forces are excluded from the Bombings Convention, not irregular non-State groups). This statement was relied upon in part to deny the benefit of the “armed forces” clause in the Terrorist Bombings Convention to an Al-Qaeda militant in Afghanistan after 9/11: US District Court for the Eastern District of New York, US v. Hausa, 258 F.Supp.3d 265, 27 June 2017, pp. 272–276. However, Hausa does not interpret the clause foremost by reference to IHL (as the US statute requires (“law of war”)), but instead by US law on statutory interpretation, the pre-9/11 context of the Terrorist Bombings Convention's adoption (when there was no armed conflict with Al-Qaeda and IHL did not apply), post-9/11 views of the US government, and the incorrect view that “armed forces” is coterminous with scope of combatant immunity (that is, solely available in international conflict).

114 While the point was not expressly reiterated when the US president presented the Nuclear Terrorism Convention (explained as containing an “identical” exclusion clause) to the Senate in 2007, nor was there any departure from the earlier position – despite the preceding seven years of debate over its meaning in the Draft UN Convention (discussed below), and the US being a leading State engaged in counter-terrorism in armed conflict: US President, letter of transmittal of the Nuclear Terrorism Convention to the US Senate, 12 July 2007.

115 18 USC § 2332f(d) (terrorist bombings); 18 USC § 2332i(d) (nuclear terrorism).

116 See, for example, Criminal Justice (Terrorist Offences) Act, 2005, Revised (Ireland), Sec. 10(6)(a) (bombings).

117 Australian Criminal Code, Sec. 72.2.

118 See the section entitled “Variants of Accommodation of IHL” below.

119 District Court of The Hague, Context Case, above note 107, para. 7.40.

120 Ibid., para. 7.41.

121 UKSC, Gul, above note 47, para. 53.

122 An issue left undecided in Ibid., paras 56–58.

123 District Court of The Hague, Context Case, above note 107, para. 7.42.

124 Ibid., para. 7.43.

125 J. Pejic, above note 52, pp. 191–192.

126 Author interview with a former coordinator of informal discussions on the Draft UN Convention, December 2019.

127 J. Pejic, above note 52, p. 192.

128 Author interview, above note 126.

129 C. Díaz-Paniagua, above note 110, p. 599 (delegate for Costa Rica, based on contemporaneous notes).

130 Ibid., p. 600 (Belgium).

131 ICRC, Terrorism and International Law, above note 51, p. 5.

132 See also M. Hmoud, above note 101, p. 1038.

133 International Criminal Tribunal for the former Yugoslavia (ICTY), Prosecutor v Tadić, Case No. IT-94-1-AR72, Appeal Chamber Decision (Interlocutory Appeal on Jurisdiction), 2 October 1995, paras 115–145.

134 UN General Assembly, Report of the Ad Hoc Committee Established by UNGA Res. 51/210 of 17 December 1996, UN Doc. A/60/37, 28 March–1 April 2005, p. 28; C. Díaz-Paniagua, above note 110, p. 661 (Tunisia).

135 See, for example, Antwerp Court of First Instance, Prosecutor v. BF et al., FD35.98.47-12, AN35.F1.1809-12, Matter I, Judgment, 11 February 2015 (Sharia4Belgium), pp. 31, 33 (affirmed by the Antwerp Court of Appeal, 2015/FP/1-7, FD35.98.47-12, Judgment, 26 January 2016, and by the Belgian Court of Cassation, P.16.0244.N, Judgment, 24 May 2016); Brussels Court of Appeal (Chamber of Indictment), Prosecutor v. U and 40 Others, Case No. 2017/2911, 14 December 2017 (regarding the PKK).

136 Amended Nuclear Material Convention, Art. 7(1).

137 Nuclear Terrorism Convention, Art. 2(1)(a).

138 Amended Nuclear Material Convention, Art. 7(1)(d).

139 Maritime Safety Protocol, Art. 3bis (1)(b)(i)–(ii); Beijing Convention, Art. 1(1)(i)(1)–(4).

140 J. Pejic, above note 52, p. 189.

141 As in the drafting of the Terrorist Bombings Convention (see UN General Assembly, Report of the Ad Hoc Committee Established by UNGA Res. 51/210 of 17 December 1996, UN Doc. A/52/37, 1997, pp. 32 (Netherlands), 43 (Switzerland), 53; UN General Assembly, Measures to Eliminate International Terrorism: Report of the Working Group, UN Doc. A/C.6/52/L.3, 10 October 1997, pp. 31, 40 (Belgium)) and the Beijing Protocol and Beijing Convention (see Damien van der Toorn, “September 11 Inspired Aviation Counter-Terrorism Convention and Protocol Adopted”, American Society of International Law Insights, Vol. 15, No. 3, 2010). Belgium proposed a bifurcated approach by which State armed forces would be excluded but other (non-State) forces would only be excluded if “acting in accordance with” IHL: Ibid., p. 31. Jordan proposed not to exclude attacks by armed forces against protected civilians: UN General Assembly, “Letter Dated 3 August 2005 from the Chairman of the Sixth Committee Addressed to the President of the General Assembly”, UN Doc. A/59/894, 12 August 2005, p. 5; C. Díaz-Paniagua, above note 111, p. 664 (Pakistan).

142 ICTY, Tadić, above note 133, para. 70.

143 ICTY, Prosecutor v Kunarac, Case Nos IT-96-23, IT-96-23/1-A, Judgment (Appeals Chamber), 12 June 2002, para. 59.

144 Nuclear Terrorism Convention, Art. 4(3); Beijing Convention, Art. 6(3).

145 C. Díaz-Paniagua, above note 110, p. 320 (South Korea).

146 UN General Assembly, Report of the Ad Hoc Committee Established by General Assembly Resolution 51/210 of 17 December 1996, UN Doc. A/57/37, 2002, Annex IV, p. 17, and UN Doc. A/58/37, 2003, pp. 11–12.

147 See, for example, the Hague Regulations of 1907, the four Geneva Conventions, AP I and AP II.

148 See, for example, GC III, Art. 4(2); AP I, Art. 43.

149 In contrast, AP II refers only to (State) High Contracting Parties, not also to parties to the conflict; Article 1 then refers to conflicts between (State) “armed forces” and “dissident armed forces” or “other organized armed groups”.

150 J. Pejic, above note 52, p. 192.

151 Ibid., p. 193.

152 See, for example, Christian Walter, “Defining Terrorism in National and International Law”, in Christian Walter, Silja Vöneky, Volker Röben and Frank Schorkopf (eds), Terrorism as a Challenge for National and International Law, Springer, Berlin, 2003, pp. 39–40.

153 C. Díaz-Paniagua, above note 110, p. 605.

154 Ibid., p. 600.

155 Sandesh Sivakumaran, The Law of Non-International Armed Conflict, Oxford University Press, Oxford, 2012, p. 180.

156 For example, persons detained by the separate civil components of an armed group, or treated in its hospitals, or prosecuted in its courts, may not be protected by common Article 3.

157 J. Pejic, above note 52, pp. 189, 193.

158 UNSC Res. 2178, 24 September 2014, para. 6.

159 UNSC Res. 1566, 8 October 2004, para. 3 is predicated on ICTC offences combined with additional general elements but it does not deal with conduct beyond ICTC offences.

160 See D. McKeever, above note 23, p. 61.

161 UNSC Res. 2253, 17 December 2015, para. 19.

162 Following the Terrorist Financing Convention, Art. 1(1).

163 UNSC Res. 2178, 24 September 2014, para. 1 (“demands that all foreign terrorist fighters disarm and cease all terrorist acts and participation in armed conflicts”) (emphasis added).

164 UNSC Res. 1371, 26 September 2001, paras 3(f)–(g) (conformity with international law, including human rights).

165 See, for example, UNSC Res. 1624, 14 September 2005, para. 4; UNSC Res. 2178, 24 September 2014, para. 5; UNSC Res. 2253, 17 December 2015, Preamble; UNSC Res. 2368, 20 July 2017, Preamble; UNSC Res. 2396, 21 December 2017, Preamble and paras 4, 18, 34, 40; UNSC Res. 2462, 28 March 2019, para. 5.

166 UNSC Res. 2462, 28 March 2019, para. 5. See D. McKeever, above note 23, p. 61.

167 UNSC Res. 2462, 28 March 2019, paras 5 (financing offences), 6 (all counterterrorism measures).

168 UNSC Res. 2396, 21 December 2017, paras 11–13; D. McKeever, above note 23, p. 63.

169 Johann Ruben Leiæ and Andreas Paulus, “Article 103”, in Bruno Simma, Daniel-Erasmus Khan, Georg Nolte, Andreas Paulus and Nikolai Wessendorf (eds), The Charter of the United Nations: A Commentary, Vol. 2, 3rd ed., Oxford University Press, Oxford, 2012, para. 17.

170 Article 103 applies only to inconsistent “agreements” and, on its ordinary meaning, it would not permit the Council to override customary IHL. This is confirmed by the travaux: see Ibid., para. 66. While the same source concludes that “the prevailing view” subsequently supports a broader view extending to custom (Ibid., para. 68), such certainty is not supported by the authorities cited, nor do the post-1945 authorities constitute (under the principles of treaty interpretation) a subsequent agreement amongst the parties which could alter the ordinary meaning confirmed by the travaux. See also F. Ní Aoláin, above note 5, para. 24.

171 European Court of Human Rights, Al-Jedda v. United Kingdom, Appl. No. 27021/08 (Grand Chamber), 7 July 2011, para. 102.

172 The reasoning in Al-Jedda was based on the special position of human rights as “purposes” of the UN under Article 2 of the UN Charter.

173 See, for example, UNGA Res. 2444 (XXIII), 19 December 1968; Hans-Peter Gasser, “The United Nations and International Humanitarian Law”, International Symposium on the 50th Anniversary of the United Nations, 19–21 October 1995 (“there is no doubt that the Charter's notion of ‘human rights …’ also includes … ‘international humanitarian law’”).

174 Cf. D. McKeever, above note 23, pp. 68–71.

175 See, for example, F. Ní Aoláin, above note 5, para. 31.

176 Cf. D. McKeever, above note 23, p. 71.

177 See ICRC Customary Law Study, above note 17, Rules 25–30, 110; AP I, Arts 8–31; AP II, Arts 7–12.

178 See ICRC Customary Law Study, above note 17, Rules 31–32, 55–56; Oxford Institute for Ethics, Law and Armed Conflict, Oxford Guidance on the Law Relating to Humanitarian Relief Operations in Situations of Armed Conflict, 2016 (Oxford Guidance), paras 11–15, 21–24.

179 F. Ní Aoláin, above note 5, para. 26.

180 For examples, see Dustin A. Lewis, Naz K. Modirzadeh and Gabriella Blum, Medical Care in Armed Conflict: International Humanitarian Law and State Responses to Terrorism, Harvard Law School, September 2015, p. iii.

181 Naz K. Modirzadeh, “Comment”, in Jessica Burniske and Naz K. Modirzadeh (eds.), Pilot Empirical Survey Study on the Impact of Counterterrorism Measures on Humanitarian Action, Harvard Law School, March 2017, p. 74.

182 Oxford Guidance, above note 178, paras 66–67, 70. See, for example, AP I, Art. 70(3)(b).

183 Oxford Guidance, above note 178, paras 82, 87–88. See, for example, GC IV, Art. 60; AP I, Art. 70(3)(c).

184 ICRC Customary Law Study, above note 17, Rule 32. See also GC IV, Art. 59; AP I, Arts 48, 70(4) (duty to protect).

185 ICRC Commentary on GC III, above note 105, Art. 3, para. 847.

186 ICRC, International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, Geneva, 2011, p. 52.

187 See, for example, ICRC Commentary on GC III, above note 105, Art. 3, paras 853–854 (ICRC protection activities).

188 Ibid.

189 GC IV, Art. 61 (in occupation, exemption from all charges, taxes or customs unless these are necessary in the interests of the economy). The same principle is arguably encouraged for the parties in other situations (including NIAC): Oxford Guidance, above note 178, pp. 27, 44.

190 Fiona Ní Aoláin, Report of the Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms while Countering Terrorism, UN Doc. A/73/45453, 3 September 2018, para. 37.

191 F. Ní Aoláin, above note 5, para. 24.

192 For an overview of some of these issues, see Dustin A. Lewis, Naz K. Modirzadeh and Jessica Burniske, The Counter-Terrorism Committee Executive Directorate and International Humanitarian Law, Harvard Law School, March 2020.

193 UNSC Res. 2462, 28 March 2019, para. 24 (financing measures).

194 UNSC Res. 2482, 19 July 2019, para. 16.

195 UNSC Res. 2462, 28 March 2019, para. 6. UNSC Res. 2482, 19 July 2019, para. 16 only “urges” States to do so.

196 Starting with UNSC Res. 1916, 19 March 2010, para. 5; the current exemption is in UNSC Res. 2551, 12 November 2020, para. 22. A more limited approach is a procedure for applying for the grant of humanitarian exemptions: see, for example, UNSC Res. 2397, 22 December 2017, para. 25 (North Korea).

197 Cf. D. McKeever, above note 23, pp. 69–71.

198 UN Security Council, Agenda: The Promotion and Strengthening of the Rule of Law in the Maintenance of International Peace and Security, UN Doc. S/PV.8499, 1 April 2019.

199 F. Ní Aoláin, above note 5, para. 34. D. McKeever, above note 23, pp. 74–75, emphasizes the need for any clauses to acknowledge the differentiated contours of protection for different forms of medical and humanitarian assistance under IHL. The Security Council could even, of course, impose higher levels of protection for medical or humanitarian activities in relation to its CTL measures than IHL provides – for instance, by explicitly requiring non-punishment of humanitarian activities in NIAC, although that could upset the balance agreed under IHL; or by ensuring that non-parties to a conflict also respect medical and humanitarian personnel and do not extraterritorially criminalize them in foreign conflicts.

200 UNSC Res. 2286, 3 May 2016, para. 3.

201 A problem identified by D. McKeever, above note 23, p. 76.

202 Cf. Ibid., p. 76.

203 Directive (EU) 2017/541 of the European Parliament and of the Council on Combating Terrorism, 15 March 2017, Recital 37, replacing Council Framework Decision 2002/475/JHA, 13 June 2002, Recital 11.

204 Council of Europe Convention on the Prevention of Terrorism, 2005, Art. 26(5). This convention's 2015 Additional Protocol on foreign terrorist fighters is qualified by renvoi to the same provision: D. McKeever, above note 23, p. 60.

205 See, for example, Criminal Justice (Terrorist Offences) Act, 2005, Revised (Ireland), Sec. 6(4)(a); Belgian Criminal Code, Art. 141bis, applied in Brussels Court of Appeal (Chamber of Indictment), Prosecutor v. U and 40 Others, Decision No. 2019/939, 8 March 2019 (acquitting PKK members on the basis that the PKK are armed forces in a NIAC and were not engaged in terrorist offences outside of it). Earlier, see Brussels Court of Appeal (Chamber of Indictment), Prosecutor v. U and 40 Others, 3 November 2016 and 14 September 2017; Antwerp Court of First Instance, Sharia4Belgium, above note 135 (Al-Nusra and IS in Syria); see also Court of Naples (Judge for Preliminary Investigations), Republic of Italy v. TJ (aka Kumar) and 29 Others, 23 June 2011; District Court of The Hague, Prosecutor v. Selliaha, Case No. BU7200 (09/748801-09), Judgment, 21 October 2011.

206 EU, Council Common Position on the Application of Specific Measures to Combat Terrorism, 2001/931/CFSP, 27 December 2001; EU, Council Regulation (EC) 2580/2001 on Specific Restrictive Measures Directed against Certain Persons and Entities with a View to Combating Terrorism, 27 December 2001.

207 OIC Convention on Combating International Terrorism, 1 July 1999 (entered into force 7 November 2002), Art. 2(a); OAU Convention, Art. 3(1).

208 District Court of The Hague, Context Case, above note 107, para. 7.35.

209 European Commission, Report from the Commission to the European Parliament and the Council Based on Article 29(1) of Directive (EU) 2017/541 of the European Parliament and of the Council of 15 March 2017 on Combating Terrorism, COM(2020) 619 final, 30 September 2020.

210 Antwerp Court of First Instance, Sharia4Belgium, above note 135, p. 33.

211 See Rogier Bartels, “When Do Terrorist Organisations Qualify as ‘Parties to an Armed Conflict’ under International Humanitarian Law?”, Military Law and Law of War Review, Vol. 56, No. 2, 2018; H. Cuyckens and C. Paulussen, above note 100, p. 556.

212 Court of Naples, TJ, above note 205.

213 Terrorist Financing Convention, Art. 21; see, similarly, Terrorist Bombings Convention, Art. 19(1); Nuclear Terrorism Convention, Art. 4(3); Maritime Safety Protocol, Art. 3; Beijing Protocol, Art. 6; Beijing Convention, Art. 6(1).

214 UN General Assembly, Report of the Working Group, above note 142, p. 31 (South Africa and Switzerland).

215 UN General Assembly, Report of the Ad Hoc Committee Established by UNGA Res. 51/210 of 17 December 1996, UN Doc. A/54/37, 1999, pp. 15, 42, 47 (France, Lebanon, Belgium).

216 UN General Assembly, Measures to Eliminate International Terrorism: Report of the Working Group, UN Doc. A/C.6/54/L.2, 26 October 1999, p. 54 (Kuwait).

217 Canadian Criminal Code, Sec. 83.01(1); see also New Zealand Terrorism Suppression Act, 2002, Sec. 5(4).

218 Swiss Criminal Code, 1937, Art. 260^quinquies1(4).

219 Supreme Court of Canada, R v. Khawaja, [2012] 3 SCR 555, 2012, paras 100–103.

220 Directive (EU) 2017/541, above note 203, Recital 38 (in implementation, see laws in Austria, Belgium, Italy and Lithuania: European Commission, above note 209, pp. 6–7); Republic of Chad, Law No. 3 on the Repression of Acts of Terrorism in the Republic of Chad, 28 April 2020, Art. 1(4) (this law also includes a general clause on “no prejudice” to IHL or human rights: Art. 1(3)); Ethiopia, Proclamation No. 1176/2020 on Prevention and Suppression of Terrorist Crimes, 25 March 2020, Art. 9(5).

221 Such as being present in a prohibited terrorist area (see UK Counter-Terrorism and Border Security Act, 2009, Sec. 4; Australian Criminal Code, Sec. 119.2(3)(a)); Denmark Criminal Code, Sec. 114(j)); associating with a terrorist organization, treasonously aiding the enemy, hostile foreign incursions, or foreign military training (Australian Criminal Code, Secs 102.8, 83.3, 80.1AA(1) and 119.5 respectively); and providing material support (Philippines Anti-Terrorism Act, 2020, Art. 13).

222 18 USC §2339A(b)(1) (material support for terrorism, excluding medicine or religious materials; medicine is interpreted as substances only: US Court of Appeals for the Second Circuit, United States v. Farhane, 634 F.3d 127, 143 (2d Cir 2011), 4 February 2011).

223 EU Council, EU Best Practices for the Effective Implementation of Restrictive Measures (Sanctions), 8519/18, 4 May 2018, para. 76.

224 Austrian Criminal Code, Art. 278(c)(3); Swiss Criminal Code, 1937, Art. 260^quinquies1 (3) (concerning terrorist financing offences only). See also the repealed Greek Penal Code, Art. 187A(8) (from 2004 to 2010) and repealed New Zealand Terrorism Suppression Act, 2002, Sec. 8(2) (from 2002 to 2007).

225 UN, “Proposal Submitted by Switzerland”, UN Doc. A/AC.252/1999/WP.1, 15 March 1999, proposed Art. 1(1); see also UN General Assembly, above note 215, p. 57.

226 UNSC Res. 2385, 14 November 2017, para. 33.

227 UNSC Res. 2462, 28 March 2019, para. 24; UNSC Res. 2482, 19 July 2019, para. 16.

228 See, for example, UK Terrorism Act, 2000, Sec. 1, applied in UKSC, Gul, above note 47; Australian Criminal Code, 1995, Sec. 100.1; Dutch Supreme Court, Opinion on Extradition of Requested Person to Republic of Turkey, ECLI:NL:HR:AF6988, Judgment, 7 May 2004, paras 3.3.7–3.3.8; District Court of The Hague, Prosecutor v. Maher H, Case No. 09/767116-14, Judgment, 1 December 2014, para. 3; District Court of The Hague, Context Case, above note 107, paras 7.23–7.29.

229 EU Common Position 2001/931/CFSP, above note 206 (concerning terrorist financing), applied in Court of Justice of the European Union (CJEU), Liberation Tigers of Tamil Eelam (LTTE) v. Council of the European Union, Case No. T-208/11, Judgment of the General Court (Sixth Chamber), 16 October 2014, paras 54–83; CJEU, A, B, C and D v. Minister van Buitenlandse Zaken, Case No. C-158/14, Judgment, 14 March 2017. Most regional treaties do not mention IHL.

230 UKSC, Gul, above note 47, paras 48–51; Dutch Supreme Court, Opinion on Extradition, above note 228, paras 3.3.7–3.3.8; District Court of The Hague, Maher H, above note 228, para. 3; cf. District Court of The Hague, Selliaha, above note 205.

231 CJEU, LTTE, above note 229, paras 54–83; CJEU, Minister, above note 229.

232 UKSC, Gul, above note 47, paras 48–51; District Court of The Hague, Maher H, above note 228, para. 3.

233 Dutch Supreme Court, Opinion on Extradition, above note 228, paras 3.3.7–3.3.8; CJEU, LTTE, above note 229; District Court of The Hague, Maher H, para. 3.

234 UKSC, Gul, above note 47, paras 47–48, 51; Court of Appeal of England and Wales, R v. Gul, [2012] EWCA Crim 280, 22 February 2012, paras 37–41.

235 CJEU, LTTE, above note 229, para. 74 (here in the context of asset freezing, but the same point applies to criminal measures under UNSC Res. 1373).

236 UKSC, Gul, above note 47, para. 53.

237 Ibid., paras 29, 33; CJEU, LTTE, above note 229.

238 UKSC, Gul, above note 47, para. 49 (approving UKSC, Al-Sirri v. Secretary of State for the Home Department, [2013] 1 AC 745, 2013, para. 68).

239 UKSC, Gul, above note 47, para. 36.