1 See, e.g., Conor Friedersdorf, “Local Anti-Drone Activism Begins: ‘If They Fly in Town, We Will Shoot Them Down’”, The Atlantic, 30 July 2013, available at: www.theatlantic.com/politics/archive/2013/07/local-anti-drone-activism-begins-if-they-fly-in-town-we-will-shoot-them-down/278198/.

2 See, e.g., Report of the Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms While Countering Terrorism, Ben Emmerson, UN Doc. A/HRC/25/59, 11 March 2014, available at: http://ap.ohchr.org/documents/dpage_e.aspx?si=A/HRC/25/59. In this context it should be noted that the current focus of international attention has been the extraterritorial targeting of specific individuals by States, even though the day may not be far when States might use armed drones within their borders. Focus has also been directed mainly at the use of drones by State actors, despite the fact that it is likely only a question of time before drones are more widely utilized by organized non-State armed groups and other non-State actors, as well as by private individuals. The Lebanon-based Hezbollah group is reported to have deployed drones laden with explosives. See Micah Zenko, Reforming US Drone Strike Policies, Council Special Report No. 65, Council on Foreign Relations, Center for Preventive Action, January 2013, p. 21, available at: www.cfr.org/wars-and-warfare/reforming-us-drone-strike-policies/p29736. More recently, in July 2014, Hamas is reported to have flown an unarmed drone over Israel. See “When Terrorists Have Drones”, Editorial, BloombergView, 22 July 2014, available at: www.bloombergview.com/articles/2014-07-22/when-terrorists-have-drones.

3 For an examination of legal and other issues related to autonomous weapons see ICRC, Autonomous Weapon Systems: Technical, Military, Legal and Humanitarian Aspects, Report of Expert Meeting, Geneva, 26–28 March 2014, available at: www.icrc.org/eng/assets/files/2014/expert-meeting-autonomous-weapons-icrc-report-2014-05-09.pdf; See also Report of the Special Rapporteur on Extrajudicial, Summary or Arbitrary Executions, Christof Heyns, UN Doc A/HRC/23/47, 9 April 2013, para. 38, available at: www.ohchr.org/Documents/HRBodies/HRCouncil/RegularSession/Session23/A-HRC-23-47_en.pdf.

4 Boyle, Michael J., “The Costs and Consequences of Drone Warfare”, International Affairs, Vol. 89, No. 1, January 2013CrossRefGoogle Scholar, p. 22, available at: http://onlinelibrary.wiley.com/doi/10.1111/1468-2346.12002/abstract.

5 Holmes, Stephen, “What's in it for Obama?”, London Review of Books, Vol. 35, No. 14, 18 July 2013, pp. 15–18Google Scholar, available at: www.lrb.co.uk/v35/n14/stephen-holmes/whats-in-it-for-obama.

6 See Henderson, Ian and Cavanagh, Bryan, “Unmanned Aerial Vehicles: Do They Pose Legal Challenges?”, in Nasu, Hitoshi and McLaughlin, Robert (eds), New Technologies and the Law of Armed Conflict, Springer, Berlin, 2014, pp. 203–204Google Scholar.

7 In this context, an occasionally stated allegation is that there is a risk that abuses are more likely to occur when a person deciding on the use of lethal force is disconnected and at a great distance from a potential adversary (the “PlayStation” mentality). See “Study on Targeted Killings”, Addendum to Report of the Special Rapporteur on Extrajudicial, Summary or Arbitrary Executions, Philip Alston, UN Doc. A/HRC/14/24/Add.6, 28 May 2010, para. 84, available at: www2.ohchr.org/english/bodies/hrcouncil/docs/14session/A.HRC.14.24.Add6.pdf. There is at present no evidence that this is the case or is more frequent with drones than with other remotely operated weapon platforms.

8 Charter of the United Nations, 24 October 1945, 1 UNTS XVI, Art. 2(4).

9 International Law Commission (ILC) Draft Articles on Responsibility of States for Internationally Wrongful Acts, November 2001, Supplement No. 10, UN Doc. A/56/10, November 2001, Art. 20. For a commentary, see Crawford, James, ILC Articles on State Responsibility: Introduction, Text and Commentaries, Cambridge University Press, Cambridge, 2002, pp. 163–165.Google Scholar

10 In this context it may be noted, for example, that the issue of whether a particular person or entity within a State had the authority to grant consent in a given case is not a question regulated by international rules on State responsibility but by international law relating to the expression of the will of the State, as well as domestic law. As regards the former, the rules on consent to treaties contained in the Vienna Convention on the Law of Treaties, 23 May 1969 (entered into force 27 January 1980), 1155 UNTS 331, are considered to provide relevant guidance. See J. Crawford, above note 9, p. 164, paras 5 and 6.

11 Given that current extraterritorial targeting by means of drones is not being conducted by the relevant States under the rubric of collective self-defence, this basis will not be explored further.

12 See Secretary-General Kofi Annan, In Larger Freedom, Report, UN Doc. A/59/2005, 21 March 2005, para. 124 (based on Report of the High Level Panel on Threats, Challenges and Change, UN Doc. A/59/565, 2 December 2004, para. 188).

13 See, e.g., Non-Aligned Movement position expressed in relation to the High Level Panel's Report in Official Records of the 85th Plenary Meeting of the United Nations General Assembly, 6 April 2005, New York, UN Doc. A/59/PV.85, pp. 14 and 15, available at: http://www.un.org/ga/59/pv.html.

14 The White House, The National Security Strategy of the United States of America, Washington, DC, September 2002, pp. 6, 15 and 16, available at: www.state.gov/documents/organization/63562.pdf.

15 Elizabeth Wilmshurst, Principles of International Law on the Use of Force by States in Self-Defence, Working Paper, Chatham House, October 2005 (Chatham House Self-Defence Principles), p. 9, available at: www.chathamhouse.org/publications/papers/view/108106.

16 See Ibid. See also Nico Schrijver and Larissa van den Herik, Leiden Policy Recommendations on Counter-terrorism and International Law, 1 April 2010, paras 27–52, available at: www.grotiuscentre.org/resources/1/Leiden%20Policy%20Recommendations%201%20April%202010.pdf.

17 International Court of Justice (ICJ), Case Concerning Oil Platforms (Islamic Republic of Iran v. United States of America), Judgment, ICJ Reports 2003, para. 73.

18 See E. Wilmshurst, Chatham House Self-Defence Principles, above note 15, p. 7.

19 See Ibid., p. 10.

20 See, e.g., Bethlehem, Daniel, “Self-Defense Against an Imminent or Actual Armed Attack by Nonstate Actors”, American Journal of International Law, Vol. 106, No. 4, 2012Google Scholar, p. 773. See also Wilmshurst, Elizabeth and Wood, Michael, “Note and Comment: Self-Defense against Nonstate Actors: Reflections on the ‘Bethlehem Principles’”, American Journal of International Law, Vol. 107, No. 2, April 2013Google Scholar, p. 390.

21 Deeks, Ashley S., “‘Unwilling or Unable’: Toward a Normative Framework for Extra-territorial Self-Defense”, Virginia Journal of International Law, Vol. 52, No. 3, 2012Google Scholar, p. 492, available at: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1971326.

22 Ibid., p. 492, note 24.

23 See ICJ, Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, ICJ Reports 2004, para. 194, in which the Court rejected Israel's claim of self-defence because it did not argue that the relevant attacks were imputable to a State.

24 See ICJ, Armed Activities on the Territory of the Congo (Democratic Republic of Congo v. Uganda), Judgment, ICJ Reports 2005, para. 116, in which the Court noted that it has “no need to respond to the contentions of the Parties as to whether and under what conditions contemporary international law provides for a right of self-defence against large-scale attacks by irregular forces”.

25 See A. S. Deeks, above note 21, p. 493, note 26.

26 See Tams, Christian J., “The Use of Force against Terrorists”, European Journal of International Law, Vol. 20, No. 2, 2009Google Scholar, p. 385.

27 See A. Deeks, above note 21, p. 495. See also E. Wilmshurst, Chatham House Self-Defence Principles, above note 15; and N. Schrijver and L. van den Herik, above note 16.

28 See UN Charter, above note 8, Arts 39–43.

29 Netherlands Advisory Committee on Issues of Public International Law (CAVV), Advisory Report on Armed Drones, Advisory Report No. 23, The Hague, July 2013 (Netherlands Advisory Committee Report), pp. 2–3, available at: http://cms.webbeat.net/ContentSuite/upload/cav/doc/CAVV_advisory_report_on_armed_drones_(English_translation_-_final)_(2).pdf. The CAVV is an independent body that advises the government, the House of Representatives and the Senate of the Netherlands on international law issues.

30 It is submitted that, as a general rule, what constitutes an “arbitrary” deprivation of life within the meaning of Article 6 of the International Covenant on Civil and Political Rights, 16 December 1966 (entered into force 23 March 1976), 999 UNTS 171 (ICCPR), is to be determined, in situations of armed conflict, with reference to the rules on the conduct of hostilities provided for in IHL, as the lex specialis. See ICJ, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, ICJ Reports 1996, para. 25.

31 John O. Brennan, Assistant to the President for Homeland Security and Counterterrorism, The Ethics and Efficacy of the President's Counterterrorism Strategy, Remarks at the Woodrow Wilson International Center for Scholars, Washington, DC, 30 April 2012, available at: www.wilsoncenter.org/event/the-efficacy-and-ethics-us-counterterrorism-strategy (emphasis added).

32 This concept has been called “naked self-defence”. See Anderson, Kenneth, “Targeted Killing and Drone Warfare: How We Came to Debate Whether There is a ‘Legal Geography of War’”, in Berkowitz, Peter (ed.), Future Challenges in National Security and Law, Hoover Institution, Stanford University, 2011Google Scholar, p. 8, available at: http://media.hoover.org/sites/default/files/documents/FutureChallenges_Anderson.pdf, stating:

The reference here is to a speech delivered in 1989 by the then US State Department Legal Adviser Sofaer, Abraham, “Terrorism, the Law, and the National Defense”, Sixth Annual Waldemar A. Solf Lecture in International Law, Military Law Review, Vol. 126, 1989Google Scholar, p. 89, available at: www.loc.gov/rr/frd/Military_Law/Military_Law_Review/pdf-files/277079~1.pdf. Anderson recognizes that the concept of naked self-defence is controversial.

33 For a comprehensive examination of this issue see Wilmshurst, Elizabeth (ed.), International Law and the Classification of Conflicts, Oxford University Press, Oxford, 2012CrossRefGoogle Scholar. See also ICRC, How is the Term “Armed Conflict” Defined in International Humanitarian Law?, Opinion Paper, ICRC, Geneva, 17 March 2008, available at: www.icrc.org/eng/assets/files/other/opinion-paper-armed-conflict.pdf.

34 Pursuant to Additional Protocol I, an armed conflict between a State and a national liberation movement can also be classified as international provided the requisite conditions have been fulfilled. Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts, 8 June 1977, 1125 UNTS 3 (entered into force 7 December 1978) (AP I), Arts 1(4), 96(3).

35 Geneva Convention 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), Art. 2; Geneva Convention 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), Art. 2; Geneva Convention Relative to the Treatment of Prisoners of War of 12 August 1949, 75 UNTS 135 (entered into force 21 October 1950) (GC III), Art. 2; Geneva Convention 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), Art. 2 (common Article 2). Under IHL, belligerent occupation is considered a type of international armed conflict. The challenges raised in relation to the criteria for determining the existence of an occupation will not be explored further in this article.

36 Pictet, Jean (ed.), Convention (III) relative to the Treatment of Prisoners of War, Geneva, 12 August 1949, Commentary, ICRC, Geneva, 1960Google Scholar, p. 23.

37 International Criminal Tribunal for the Former Yugoslavia (ICTY), The Prosecutor v. Dusko Tadić, Decision on the Defence Motion for Interlocutory Appeal on Jurisdiction, Case No. IT-94-1-A, 2 October 1995, para. 70, available at: http://www.refworld.org/docid/47fdfb520.html.

38 See Mary Ellen O'Connell, Final Report on the Meaning of Armed Conflict in International Law, Committee on the Use of Force, International Law Association, The Hague, 2010, available at: www.ila-hq.org/en/committees/index.cfm/cid/1022.

39 For a discussion of the various positions, see Dapo Akande, “Classification of Armed Conflicts: Relevant Legal Concepts”, in E. Wilmshurst (ed.), above note 33, p. 72.

40 Ibid., p. 75.

41 See, e.g., European Parliament Resolution on the Use of Armed Drones, Plenary Sitting, 2014/2567(RSP), 25 February 2014, para. E, available at: www.europarl.europa.eu/sides/getDoc.do?pubRef=-//EP//TEXT+MOTION+P7-RC-2014-0201+0+DOC+XML+V0//EN.

42 See Greenwood, Christopher, “Scope of Application of International Humanitarian Law”, in Fleck, Dieter (ed.), The Handbook of Humanitarian Law in Armed Conflicts, Oxford University Press, Oxford, 1995Google Scholar, p. 43. “The application of IHL is not dependent on a formal declaration of war.”

43 Except as mentioned in above note 34.

44 Given that NIACs under the Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of Non-International Armed Conflicts of 8 June 1977, 1125 UNTS 609 (entered into force 7 December 1987) (AP II), have to fulfil certain conditions not found in common Article 3 and that they are far less common, they will not be further discussed here. See AP II, Art. 1(2); GC I, Art. 3; GC II, Art. 3; GC III, Art. 3; and GC IV, Art. 3 (common Article 3). It is generally accepted that the threshold found in Article 1(2) of AP II, which excludes internal disturbances and tensions from the definition of NIAC, also applies to common Article 3. Given that NIACs under AP II have to fulfil certain conditions not found in common Article 3 and that they are far less common, they will not be further discussed here.

45 See Schindler, Dietrich, “The Different Types of Armed Conflicts According to the Geneva Conventions and Protocols”, in Collected Courses of the Hague Academy of International Law, Vol. 163, Martinus Nijhoff, The Hague, 1979Google Scholar, p. 147. For a detailed analysis of this criterion see ICTY, The Prosecutor v. Fatmir Limaj, Case No. IT-03-66-T, Judgment, 30 November 2005, paras 94–134.

46 For a detailed analysis of this criterion, see Limaj, above note 45, paras 135–170.

47 Tadić, above note 37, para. 70.

48 For a possible typology see ICRC, Report on IHL and the Challenges of Contemporary Armed Conflicts, Report presented to the 31st International Conference of the Red Cross and Red Crescent, ICRC, Geneva, 28 November–1 December 2011 (2011 ICRC Challenges Report), pp. 9–11, available at: www.icrc.org/eng/assets/files/red-cross-crescent-movement/31st-international-conference/31-int-conference-ihl-challenges-report-11-5-1-2-en.pdf.

49 See, e.g., Schmitt, Michael N., “Charting the Legal Geography of Non-International Armed Conflict”, International Law Studies, Vol. 90, US Naval War College, 2014Google Scholar, p. 11. “In particular, there is growing acceptance of the proposition that IHL applies to ‘spillover’ conflicts in which government armed forces penetrate the territory of a neighboring State in order to engage organized armed groups operating in border areas … There is certainly State practice and scholarly support for this interpretation” (footnotes omitted).

50 Statute of the International Criminal Tribunal for Rwanda (ICTR), UN SC Res. 955 Annex, UN Doc. S/RES/955, 8 November 1994, Art. 1.

51 A specific legal and practical issue that is the subject of much debate and on which no majority opinion may currently be discerned is how far into a neighbouring State the applicability of IHL extends in case of a spillover NIAC: does it extend to the entire territory of the adjacent country or only to the area of hostilities between the parties? This question, while important, will not be further explored here.

52 See, inter alia, CNN, “Gates Calls Pakistan ‘Most Worrisome’”, 1 March 2009, available at: http://edition.cnn.com/2009/US/03/01/us.afghanistan/. “Meanwhile, the war is spilling over into Pakistan, where the Taliban have long had a foothold in the tribal areas along the mountainous border.”

53 A subset of this type of NIAC is one in which UN forces, or forces under the aegis of a regional organization (such as the African Union), are sent to support a host government involved in hostilities against one or more organized armed groups in its territory. See 2011 ICRC Challenges Report, above note 48, p. 10.

54 See Francoise J. Hampson, “Afghanistan 2001–2010”, in E. Wilmshurst, above note 33, p. 251 (citing, inter alia, the ICRC's view). See also ibid., p. 252, where the author submits that the IAC in Afghanistan ended either with the adoption of UN Security Council Resolution 1386 (2001) or with the inauguration of Hamid Karzai as president after the Loya Jirga and the establishment of an Afghan transitional government in June 2002. The latter, ICRC view is adopted here.

55 For a more detailed elaboration of the criteria on the basis of which a State (or States) may be considered to have become a party to a pre-existing NIAC in a host State, see Ferraro, Tristan, “The Applicability and Application of IHL to Multinational Forces”, International Review of the Red Cross, Vol. 95, No. 891, 2013CrossRefGoogle Scholar, p. 561.

56 See Agence France-Presse, “Key Dates in French–Led Mali Intervention”, Global Post, 1 July 2013, available at: www.globalpost.com/dispatch/news/afp/130701/key-dates-french-led-mali-intervention.

57 See Robert Chesney, “The United States as a Party to an AQAP-Specific Armed Conflict in Yemen”, Lawfare, 31 January 2012, available at: www.lawfareblog.com/2012/01/yemen-armed-conflic/. “[T]he U.S. has not merely provided various forms of assistance to the government of Yemen in its fight with AQAP, but also has attacked AQAP targets in Yemen in its own right at least seventeen times over the past few years, including a strike yesterday. I think the better view, then, is that we are party to the Yemen NIAC, and that our uses of force there implicate IHL as a result (quite apart from arguments about the existence and geographic scope of conflict elsewhere or with respect to other entities)” (emphasis in original).

58 The domestic legal basis is the Authorization for the Use of Military Force (AUMF), Pub. L. 107-40, 115 Stat. 224, adopted by Congress in S.J. Res. 23 on 14 September 2001 and signed by President George W. Bush on 18 September 2001, available at: www.gpo.gov/fdsys/pkg/PLAW-107publ40/html/PLAW-107publ40.htm. For an explication of how the AUMF is being applied, see Stephen W. Preston, General Counsel, Department of Defense, Prepared Statement on The Legal Framework Under U.S. Law for Current Military Operations, Committee on Foreign Relations, United States Senate, 21 May 2014, available at: www.foreign.senate.gov/download/preston-testimony-05-21-14.

59 US Supreme Court, Hamdan v. Rumsfeld, 548 US 57, 2006, p. 67, available at: http://www.law.cornell.edu/supct/pdf/05-184P.ZO. (“[T]he Government asserts, that Common Article 3 does not apply to Hamdan because the conflict with al Qaeda, being ‘international in scope,’ does not qualify as a ‘conflict not of an international character.’”)

60 See US Department of State, Report of the United States of America Submitted to the UN High Commissioner for Human Rights In Conjunction with the Universal Periodic Review, 2010, para. 84, available at: www.state.gov/documents/organization/146379.pdf. “Individuals detained in armed conflict must be treated in conformity with all applicable laws, including Common Article 3 of the 1949 Geneva Conventions, which the President and the Supreme Court have recognized as providing ‘minimum’ standards of protection in all non-international armed conflicts, including in the conflict with Al Qaeda.”

61 According to President Obama: “Under domestic law, and international law, the United States is at war with al Qaeda, the Taliban, and their associated forces.” See President Barack Obama, Remarks by the President at the National Defense University, Office of the Press Secretary, Washington, DC, 23 May 2013, available at: www.whitehouse.gov/the-press-office/2013/05/23/remarks-president-national-defense-university. The Taliban is only targeted in Afghanistan: “Beyond the Afghan theater, we only target al Qaeda and its associated forces.” See also, e.g., US Department of Justice, Office of Legal Counsel, Memorandum for the Attorney-General Re: Applicability of Federal Criminal Laws and the Constitution to Contemplated Lethal Operations Against Shaykh Anwar al-Aulaqi, 16 July 2010 (released publicly 23 June 2014), p. 24, available at: http://fas.org/irp/agency/doj/olc/aulaqi.pdf. “[T]he contemplated DoD operation would occur in Yemen, a location that is far from the most active theater of combat between the United States and al-Qaida. That does not affect our conclusion, however, that the combination of facts present here would make the DoD operation in Yemen part of the non-international armed conflict with al-Qaida.”

62 In his NDU speech President Obama stated: “Today, the core of al Qaeda in Afghanistan and Pakistan is on the path to defeat. … Instead, what we've seen is the emergence of various al Qaeda affiliates. From Yemen to Iraq, from Somalia to North Africa, the threat today is more diffuse, with Al Qaeda's affiliates in the Arabian Peninsula – AQAP – the most active in plotting against our homeland.” B. Obama, above note 61.

63 See Cora Currier, “Who Are We at War With? That's Classified”, ProPublica, 26 July 2013, available at: www.propublica.org/article/who-are-we-at-war-with-thats-classified.

64 For a succinct overview of Obama administration views, with links to key speeches by administration officials on the issue over the past few years, see Jonathan Masters, Targeted Killings, Backgrounder, Council on Foreign Relations, Washington, DC, 23 May 2013, available at: www.cfr.org/counterterrorism/targeted-killings/p9627.

65 See, inter alia, 2011 ICRC Challenges Report, above note 48, p. 10.

66 See J. Brennan, above note 31. “Al-Qa'ida leaders continue to struggle to communicate with subordinates and affiliates. Under intense pressure in the tribal regions of Pakistan, they have fewer places to train and groom the next generation of operatives. They're struggling to attract new recruits. Morale is low, with intelligence indicating that some members are giving up and returning home, no doubt aware that this is a fight they will never win. In short, al-Qa'ida is losing, badly.” See also Tim Lister, “How ISIS is Overshadowing al Qaeda”, CNN, 30 June 2014, available at: http://edition.cnn.com/2014/06/30/world/meast/isis-overshadows-al-qaeda/.

67 See Charlie Savage, “Debating the Legal Basis for the War on Terror”, New York Times, 16 May 2013, available at: www.nytimes.com/2013/05/17/us/politics/pentagon-official-urges-congress-to-keep-statute-allowing-war-on-terror-intact.html?_r=0. “Mr. Taylor [Acting General Counsel of the Pentagon] said that as a matter of domestic law, the authorization did grant such authority if groups in those countries had affiliated themselves with the original Al Qaeda and became ‘co-belligerents' in the conflict.”

68 For an examination of the relationship between armed conflict and terrorism, see Pejic, Jelena, “Armed Conflict and Terrorism: There Is a (Big) Difference”, in de Frias, Ana Maria Salinas, Samuel, Katja L. H. and White, Nigel D. (eds), Counter-Terrorism: International Law and Practice, Oxford University Press, Oxford, 2012, pp. 171–204Google Scholar.

69 Henckaerts, Jean-Marie and Doswald-Beck, Louise (eds), Customary International Humanitarian Law, Vol. 1: Rules, and Vol. 2: Practice, Cambridge University Press, Cambridge, 2005 (ICRC Customary Law Study)CrossRefGoogle Scholar.

70 This is not to say that there cannot be lawful use of force by State agents under human rights law. Such use of force, however, is always undertaken in response to a previously unlawful act by an individual or group of persons. That is not the case with direct participation in hostilities, which is either explicitly allowed, or is not prohibited under IHL. Thus, direct participation in hostilities is not a war crime under IHL.

71 See Marco Sassòli and Lindy Rouillard, “La définition du terrorisme et le droit international humanitaire”, Revue québécoise de droit international, Studies in Honour of Katia Boustany, 2007, p. 31. See also the debate between Sassòli, Marco and Shany, Yuval, “Should the Obligations of States and Armed Groups Under International Humanitarian Law Really Be Equal?”, International Review of the Red Cross, Vol. 93, No. 882, 2011CrossRefGoogle Scholar, p. 431.

72 The principle of equality of parties, or “equality of belligerents”, under IHL is not only legally important, but also serves to de facto enhance compliance with the norms by all sides involved.

73 AP I, Art. 48; ICRC Customary Law Study, above note 69, Rule 1.

74 See AP I, Art. 51(3) and AP II, Art. 13(3); ICRC Customary Law Study, above note 69, Rule 6.

75 AP I, Art. 50(1). For an evaluation of the customary law status of this rule, see the ICRC Customary Law Study above note 69, commentary to Rule 6, pp. 23–24. See also Tallinn Manual on the International Law Applicable to Cyber Warfare, NATO Cooperative Cyber Defence Centre of Excellence, Cambridge University Press, Cambridge, April 2013, Rule 33, available at: www.ccdcoe.org/tallinn-manual.html.

76 AP I, Art. 48; ICRC Customary Law Study, above note 69, Rule 7.

77 ICRC Customary Law Study, above note 69, Rule 10.

78 AP I, Art. 51(4); ICRC Customary Law Study, above note 69, Rules 11 and 12.

79 AP I, Art. 51(5)(b); ICRC Customary Law Study, above note 69, Rule 14.

80 AP I, Arts 57 and 58; ICRC Customary Law Study, above note 69, Rules 15–24.

81 See Lubell, Noam, “Challenges in Applying Human Rights Law to Armed Conflict”, International Review of the Red Cross, Vol. 87, No. 860, 2005CrossRefGoogle Scholar, p. 745, available at: www.icrc.org/eng/assets/files/other/irrc_860_lubell.pdf. “For example, under human rights law and the rules of law enforcement, when a State agent is using force against an individual, the proportionality principle measures that force in an assessment that includes the effect on the individual himself, leading to a need to use the smallest amount of force necessary and restricting the use of lethal force.”

82 For an excellent overview of the issue, see Queguiner, Jean-Francois, “Precautions Under the Law Governing the Conduct of Hostilities”, International Review of the Red Cross, Vol. 88, No. 864, 2006CrossRefGoogle Scholar, available at: www.icrc.org/eng/resources/documents/article/review/review-864-p793.htm.

83 Nils Melzer, Human Rights Implications of the Usage of Drones and Unmanned Robots in Warfare, Study, European Parliament, Directorate-General for External Policies, Policy Department, May 2013, p. 24, available at: www.europarl.europa.eu/delegations/en/studiesdownload.html?languageDocument=EN&file=92953.

84 AP I, Art. 58; ICRC Customary Law Study, above note 69, Rules 22–24.

85 AP I, Art. 43(2).

86 AP I, Art. 51(1) and AP II, Art. 13(1).

87 AP I, Art. 51(2) and AP II, Art. 13(2).

88 AP I, Art. 51(3) and AP II, Art. 13(3).

89 ICRC, Report on IHL and the Challenges of Contemporary Armed Conflicts, Report presented to the 30th International Conference of the Red Cross and Red Crescent, ICRC, Geneva, 26–30 November 2007, pp. 15–16 (on which part of this section is based), available at: www.icrc.org/eng/assets/files/other/ihl-challenges-30th-international-conference-eng.pdf. “They included, for example, the production of arms, equipment, food and shelter, as well as economic, administrative and political support. Traditionally, only a small minority of civilians became involved in the actual conduct of military operations.” Ibid., p. 15.

90 Melzer, Nils, Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law, ICRC, Geneva, 2009Google Scholar (Interpretive Guidance), available at: www.icrc.org/eng/resources/documents/article/review/review-872-p991.htm. For scholarly articles criticizing certain aspects of the Interpretive Guidance, and Nils Melzer's response to those views, see New York University Journal of International Law and Politics, Vol. 42, No. 3, 2010, available at: http://nyujilp.org/print-edition/, which is devoted to that topic.

91 Pursuant to the Interpretive Guidance, in IAC all persons who are neither members of the armed forces of a party to the conflict nor participants in a levée en masse are entitled to protection against direct attack unless and for such time as they take a direct part in hostilities. Members of irregular armed forces (militia, volunteer corps, etc.) whose conduct is attributable to a State party to a conflict are considered part of its armed forces. They are not deemed civilians for the purposes of the conduct of hostilities even if they fail to fulfil the criteria required by IHL for combatant privilege and POW status. Membership in irregular armed forces belonging to a party to the conflict is to be determined based on the same functional criteria that apply to organized armed groups in NIAC.

92 See Report of the UN Special Rapporteur on Extrajudicial, Summary or Arbitrary Executions, Philip Alston, above note 7, para. 65.

93 Interpretive Guidance, above note 90, p. 77, Recommendation IX.

94 See W. Hays Parks, “Part IX of the ICRC ‘Direct Participation in Hostilities' Study: No Mandate, No Expertise, and Legally Incorrect”, New York University Journal of International Law and Politics, Vol. 42, No. 3, p. 799.

95 See, for example, NATO, Glossary of Terms and Definitions, AAP-6V, M-5, p. 2; US Department of the Army, Field Manual 27–10, 1956, § 3; US Department of the Navy, The Commander's Handbook on the Law of Naval Operations, NWP 1–14M/MCWP 5–12-1/COMDTPUB P5800.7A, 2007, § 5.3.1, p. 5–2.; French Ministry of Defence, Manuel de Droit des Conflits Armés, 2001, pp. 86 ff.; German Federal Ministry of Defence, Triservice Manual ZDv 15/2: Humanitarian Law in Armed Conflicts, August 1992, §130; Switzerland, Swiss Army, Regulations 51.007/IV, Bases légales du comportement à l'engagement, 2005, § 160. Historically, the modern concept of military necessity has been strongly influenced by the definition provided in Instructions for the Government of Armies of the United States in the Field, General Orders No. 100, 24 April 1863 (Lieber Code), Art. 14.

96 Interpretive Guidance, above note 90, p. 78.

97 Ibid., p. 80.

98 See Anthony Dworkin, Drones and Targeted Killing: Defining a European Position, Policy Brief, European Council on Foreign Relations, London, 3 July 2013, p. 5, available at: http://ecfr.eu/publications/summary/drones_and_targeted_killing_defining_a_european_position211. See also N. Melzer, above note 83, pp. 34–35.

99 For a comprehensive review of the issue, see Heller, Kevin Jon, “‘One Hell of a Killing Machine’: Signature Strikes and International Law”, Journal of International Criminal Justice, Vol. 11, No. 1, 2013CrossRefGoogle Scholar, p. 1, available at: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2169089, citing Klaidman, Daniel, Kill or Capture: The War on Terror and the Soul of the Obama Presidency, Houghton Mifflin Harcourt, New York, 2012Google Scholar, p. 41.

100 Those in which the targeting entity has a “high degree of confidence” that it knows the precise identity of the target. See K. Heller, above note 99, p. 2.

101 See ibid., p. 11 and note 52.

102 For an examination of the practice on its own, see N. Melzer, above note 83, p. 35. For an examination of the practice as a subset of signature strikes, see K. Heller, above note 99, p. 11.

103 See I. Henderson and B. Cavanagh, above note 6, p. 208.

104 See K. Anderson, above note 32.

105 See, e.g., C. Greenwood, above note 42, p. 51 (area). See also Dinstein, Yoram, War, Aggression and Self-Defense, Cambridge University Press, Cambridge, 2011CrossRefGoogle Scholar, p. 19.

106 Parts of the national territory of the parties to an IAC, such as demilitarized zones, including hospital and safety zones, as well as neutralized zones and non-defended localities, are subject to a special IHL regime that will not be examined here.

107 For an examination of the notion of “zone of active hostilities”, see Daskal, Jennifer C., “The Geography of the Battlefield: A Framework for Detention and Targeting Outside the ‘Hot’ Conflict Zone”, University of Pennsylvania Law Review, Vol. 161, No. 5, 2013, pp. 1165–1234Google Scholar.

108 Common Art. 3(1).

109 ICTY, The Prosecutor v. Dragoljub Kunarac, Radomir Kovač and Zoran Vuković, Case No. IT-96–23 & IT-96–23/1-A, Judgment, 12 June 2002, para. 57, available at: www.icty.org/x/cases/kunarac/acjug/en/kun-aj020612e.pdf. It may be noted that that the ICTY Appeals Chamber's view on the geographical scope of application of IHL seems to have evolved from the initial position taken in the 1995 Tadić Decision, above note 37, paras. 67–69.

110 ICTR, The Prosecutor v. Laurent Semanza, Case No. ICTR-97-20-T, Judgment, 15 May 2003, para. 367, available at: www.refworld.org/docid/48abd5a30.html.

111 Interpretive Guidance, above note 90, p. 78.

112 Ibid., p. 77, Recommendation IX.

113 See Gloria Gaggioli, The Use of Force in Armed Conflicts: Interplay Between the Conduct of Hostilities and Law Enforcement Paradigms, Report of Expert Meeting, ICRC, Geneva, November 2013, available at: www.icrc.org/eng/assets/files/publications/icrc-002-4171.pdf.

114 David Kretzmer, Aviad Ben-Yehuda and Meirav Furth, “Thou Shall Not Kill: The Use of Lethal Force in Non-International Armed Conflicts”, Israel Law Review, Vol. 47, No. 2, 2014.

115 Ibid., p. 194.

116 Ibid., p. 224.

117 Ibid., p. 222.

118 See Netherlands Advisory Committee Report, above note 29, p. 3.

119 M. Schmitt, above note 49, p. 16.

120 The term “non-belligerent” is used here in the generic sense to signify a State not taking part in an armed conflict, in distinction to the status of neutrality of a State in an IAC, as described below.

121 N. Melzer, above note 83, p. 21. For a similar position see Schmitt, Michael N., “Extraterritorial Lethal Targeting: Deconstructing the Logic of International Law”, Columbia Journal of Transnational Law, Vol. 52, 2013Google Scholar, p. 99.”

122 Netherlands Advisory Committee Report, above note 29, p. 3.

123 GC IV, Part III, § I, Arts 27–34.

124 GC IV, Part III, § II, Arts 35–46.

125 GC IV, Part III, § II, Arts 47–78.

126 GC III, Art. 4A(2).

127 Thus, for example, in Article 4B(2), the Third Geneva Convention extends POW treatment to members of the armed forces of a belligerent who have been received by a neutral State (in which case they must be interned in accordance with the 1907 Hague Convention (V) Respecting the Rights and Duties of Neutral Powers and Persons in Case of War on Land). Similarly, the First and Second Geneva Conventions specify, in Articles 4 and 5 respectively, the treatment that neutrals must afford to wounded, sick or shipwrecked members of the armed forces of the belligerents, including medical personnel and chaplains, received or interned in their territory.

128 The essentially territorial scope of application of IHL treaties in IAC does not mean that IHL will cease to operate in favor of individual protected persons who are removed from belligerent territory, as long as they remain in enemy hands.

129 AP I, Art. 1(3).

130 AP I, Art. 49(1).

131 AP I, Art. 49(2): “The provisions of this Protocol with respect to attacks apply to all attacks in whatever territory conducted, including the national territory belonging to a party to the conflict but under the control of an adverse party.”

132 Sandoz, Yves, Swinarski, Christophe and Zimmermann, Bruno (eds), Commentary on the Additional Protocols of June 8 1977 to the Geneva Conventions of 12 August 1949, ICRC, Geneva, 1987Google Scholar (AP I Commentary), paras 1883–1891.

133 Eric David, Principes de droit des conflits armés, Bruylant, Brussels, 2002, p. 240.

134 See AP I Commentary to Art. 49(2) at para. 1891. “Finally this paragraph makes it clear, as implied in paragraph 4, that the provisions of the Protocol relating to attacks and the effects thereof apply to the whole of a population present in the territory of a party to the conflict, even if it is under enemy control – as does Part II of the Fourth Convention” (emphasis added).

135 AP I, Art. 3(b).

136 For an overview of the law of neutrality and arguments in favour of its continued validity, see von Heinegg, Wolff Heintschel, “‘Benevolent’ Third States in International Armed Conflicts: The Myth of the Irrelevance of the Law of Neutrality”, in Schmitt, Michael and Pejic, Jelena (eds), International Law and Armed Conflict: Exploring the Faultlines, Martinus Nijhoff, Leiden/Boston, 2007, pp. 543–568CrossRefGoogle Scholar.

137 See Peter Hostettler and Olivia Danai, “Neutrality in Land Warfare”, in Rüdiger Wolfrum (ed.), Max Planck Encyclopedia of Public International Law, Oxford Public International Law, §2, General Rules, paras 7–10, available at: http://opil.ouplaw.com/view/10.1093/law:epil/9780199231690/law-9780199231690-e347?rskey=UkNyhH&result=1&prd=EPIL.

138 For the application of the rules of neutrality to air warfare, see Peter Hostettler and Olivia Danai, “Neutrality in Air Warfare”, in Rüdiger Wolfrum (ed.), Max Planck Encyclopedia of Public International Law, Oxford Public International Law, paras 1–23, available at: http://opil.ouplaw.com/view/10.1093/law:epil/9780199231690/law-9780199231690-e346?rskey=J0TtA8&result=2&prd=EPIL.

139 P. Hostettler and O. Danai, above note 137, paras 3–4. There are also different views on this, as noted in W. H. von Heinegg, above note 136, p. 556.

140 See Bothe, Michael, “The Law of Neutrality”, in Fleck, Dieter (ed.), The Handbook of Humanitarian Law in Armed Conflicts, Oxford University Press, Oxford, 1995Google Scholar, p. 487.

141 N. Melzer, above note 83, p. 21.

142 Ibid.

143 AP II provides in Article 1(1): “This Protocol, which develops and supplements Article 3 common to the Geneva Conventions of 12 August 1949 without modifying its existing conditions of application, shall apply to all armed conflicts which are not covered by Article 1 of the Protocol Additional to the Geneva Conventions … and which take place in the territory of a High Contracting Party between its armed forces and dissident armed forces or other organized armed groups.” Given the different legal threshold for the applicability of AP II, due to which the hypothetical scenario is outside the purview of the Protocol, this treaty will not be further mentioned here.

144 For example, the European Union and its member States have consistently stressed a human rights (i.e., criminal justice) approach to the fight against terrorism (which includes persons associated with organized non-State armed groups designated as “terrorist”), without mention in EU documents or in joint statements with the US of a “global war on terrorism” or of a “global battlefield”. For the EU approach, see, e.g., EU Council Secretariat, The European Union and the Fight Against Terrorism, Factsheet, Brussels, 2 October 2009, available at: www.consilium.europa.eu/uedocs/cmsUpload/Factsheet-fight%20against%20terrorism%20091002.EN.revised.PDF. See also Joint Statement, EU–US Summit, Brussels, 140326/02, 26 March 2014, para. 13, available at: www.eeas.europa.eu/statements/docs/2014/140326_02_en.pdf. “We cooperate against terrorism in accordance with respect for human rights.”

145 ICCPR, Art. 6; Basic Principles on the Use of Force and Firearms by Law Enforcement Officials, adopted by the Eighth UN Congress on the Prevention of Crime and the Treatment of Offenders, Havana, Cuba, 27 August–7 September 1990 (BPUFF), available at: www.ohchr.org/EN/ProfessionalInterest/Pages/UseOfForceAndFirearms.aspx. If in this scenario the non-belligerent State did not consent to the use of force in its territory, a separate IAC between the two States will also be deemed to exist as a matter of law.

146 BPUFF, Principle 9.

147 Ibid.

148 N. Lubell, above note 81, p. 745.

149 Netherlands Advisory Committee Report, above note 29, p. 3.

150 M. Schmitt, above note 49, p. 18.

151 Two specific issues have been flagged in this regard. The first is the legal regime that would be applicable to the possible use of force against bases established by a non-State armed group in the territory of a non-belligerent State for training and logistical purposes in relation to an ongoing NIAC. See M. Schmitt, above note 49, p. 17. It is submitted that the same question should also be posed with respect to the legal regime that would be applicable to the targeting of the military bases of States located in non-belligerent territory from which military operations are conducted in relation to an ongoing NIAC. The second issue is the legal regime that would be applicable to cyber-attacks launched by and against non-State armed groups from and through non-belligerent territory. Both questions will clearly require further examination as State practice evolves.