1 Reprinted in Fleck, Dieter et al. (eds), The Handbook of Humanitarian Law in Armed Conflict, Oxford University Press, Oxford, 2004, p. 14Google Scholar.

2 Judge advocates are otherwise known as military lawyers. For their role in combat, see Lohr, Michael F. and Gallotta, Steve, ‘Legal support in war: the role of military lawyers’, in Chicago Journal of International Law, Vol. 4, No. 2, Fall 2003, pp. 465–478Google Scholar.

3 Protocol Additional to the Geneva Conventions of 12 August 1949 and relating to the Protection of Victims of International Armed Conflicts (Protocol I) (hereinafter API), 8 June 1977, 1125 UNTS 3, Arts. 51(5)(b) and 57(2)(a)(iii) and (b), available at: http://www.unhcr.org/refworld/docid/3ae6b36b4.html (last visited 2 November 2012).

4 Subject to the commander's guidance and approval, a planning cell develops the campaign plan and specific military operations for the unit (i.e., division) and subordinate units (i.e., brigades), and a fires and effects coordination cell develops the non-lethal and lethal targets sets for approval and appropriate action (e.g., a non-lethal target could be a jobs initiative programme or a disarmament, demobilization, and reintegration initiative).

5 Tanaka, Yuki and Young, Marilyn B. (eds), Bombing Civilians: A Twentieth-Century History, New Press, London, 2009, p. 209Google Scholar.

6 US Department of the Army Judge Advocate Generals Legal Center and School, Law of War Deskbook, International and Operational Law Department, Charlottesville, Virginia, 2010, p. 23Google Scholar (hereinafter LOW DB).

7 Henderson, Ian, The Contemporary Law of Targeting: Military Objectives, Proportionality and Precautions in Attack Under Additional Protocol I, Martinus Nijhoff, Leiden, 2009, p. 247CrossRefGoogle Scholar. For brevity, certain provisions concerning the civilian population are not discussed herein, such as Articles 53 through 56 of API pertaining to, inter alia, special objects (e.g., places of worship, etc.) and the protection of the environment.

8 API, above note 3, Art. 48.

9 API, above note 3, Arts 48 and 52(1); Henckaerts, Jean-Marie and Doswald-Beck, Louise (eds), International Committee of the Red Cross, Customary International Humanitarian Law, Vol. 1, Rules, (hereinafter ICRC Study) Cambridge University Press, Cambridge, 2005Google Scholar, Rule 25, available at: www.icrc.org/…/customary-international-humanitarian-law-i-icrc-eng.pdf (last visited 2 November 2012).

10 API, above note 3, Art. 49(1).

11 I. Henderson, above note 7, pp. 51–52; API, above note 3, Art. 52(2); ICRC Study, above note 9, p. 32.

12 I. Henderson, above note 7, pp. 54–60.

13 Ibid., p. 73.

14 Sandoz, Yves, et al. , Commentary on The Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949 (hereinafter ICRC Commentary), ICRC, Geneva, 17 October 1987Google Scholar, para. 2208, available at: http://www.loc.gov/rr/frd/Military_Law/RC_commentary-1977.html (last visited 2 November 2012).

15 I. Henderson, above note 7, p. 71.

16 ICRC Commentary, above note 14, para. 2209.

17 ICRC Study, above note 9, pp. 26–36.

18 API, above note 3, Art. 51(2).

19 Ibid., Art. 50(1).

20 I. Henderson, above note 7, p. 81.

21 ICRC Study, above note 9, Rules 3 and 4, pp. 11–16; Geneva Convention Relative to the Treatment of Prisoners of War (Third Geneva Convention), 12 August 1949, 75 UNTS 135, Art. 4(A)(3), available at: http://www.unhcr.org/refworld/docid/3ae6b36c8.html (last visited 2 November 2012); API, above note 3, Art. 43(1); I. Henderson, above note 7, pp. 80–81.

22 Protocol Additional to the Geneva Conventions of 12 August 1949 and Relating to the Protection of Victims of Non-International Armed Conflicts (Protocol II) (hereinafter APII), 8 June 1977, 1125 UNTS 609, Art. 1, available at: http://www.unhcr.org/refworld/docid/3ae6b37f40.html (last visited 2 November 2012); ICRC Study, above note 9, p. 12.

23 API, above note 3, Art. 51(3); ICRC Study, Rule 3, above note 9, pp. 19–24.

24 ICRC Study, Rule 6, above note 9, p. 21.

25 LOW DB, above note 6, pp. 99–100 (citing ICRC, Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law (2008)Google Scholar, available at: http://www.icrc.org/eng/war-and-law/contemporary-challenges-for-ihl/participation-hostilities/index.jsp (last visited 1 November 2012).

26 API, above note 3, Art. 51(3).

27 ICRC Study, above note 9, p. 19 (Rule 5).

28 Ibid., 21 (Rule 6).

29 I. Henderson, above note 7, pp. 95–97. For a concise discussion, see Program on Humanitarian Policy and Conflict Resolution, Commentary on the HPCR Manual on International Law Applicable to Air and Missile Warfare, Harvard University Press, Cambridge, MA, 2009, pp. 117–124Google Scholar available at: http://www.ihlresearch.org/amw/manual/ (last visited 1 November 2012) (hereinafter HPCR Commentary).

30 Melzer, Nils, Targeted Killing in International Law, Oxford University Press, Oxford, 2009, p. 355Google Scholar.

31 API, above note 3, Arts 51(4)–(5)(a); ICRC Study, above note 9, pp. 37–50.

32 Rogers, A. P. V., Law on the Battlefield, Manchester University Press, Manchester, 2004, p. 23Google Scholar.

33 Ibid., p. 24.

34 Dinstein, Yoram, The Conduct of Hostilities Under the Law of International Armed Conflict, Cambridge University Press, Cambridge, 2004, p. 118CrossRefGoogle Scholar.

35 US Department of Defense, Report to Congress: Conduct of the Persian Gulf War (hereinafter DoD Report), Pentagon, Washington, D.C., 1992, p. 698Google Scholar, available at: www.ndu.edu/library/epubs/cpgw.pdf (last visited 2 November 2012).

36 ICRC Study, above note 9, pp. 38–39 (per Rule 11 ‘[n]o official contrary practice was found with respect to either international or non-international armed conflicts’).

37 API, above note 3, Art. 51(5)(b); ICRC Study, Rule 14, above note 9, pp. 46–50. I. Henderson, above note 7, pp. 180–181; A. P. V. Rogers, above note 32, p. 17.

38 Basic Principles on the Use of Force and Firearms by Law Enforcement Officials, 7 September 1990, Principle 5, available at: http://www2.ohchr.org/english/law/firearms.htm (last visited 1 November 2012).

39 For an excellent examination of the lawfulness of state-sponsored targeted killings under international human rights law (i.e., the law enforcement paradigm) and international humanitarian law (i.e., the conduct of hostilities paradigm), see generally N. Melzer, above note 30.

40 API, above note 3, Art. 57; ICRC Study, above note 9, pp. 51–67; Hague Convention IV, Respecting the Laws and Customs of War on Land, 18 October 1907, 36 Stat. 2277, Art. 2(3) (hereinafter Hague IV).

41 API, above note 3, Art. 57(1).

42 API, above note 3, Art. 57(2)(a)(iii); ICRC Study, above note 9, pp. 51–61.

43 Compare US Department of the Army Judge Advocate Generals Legal Center and School, Operational Law Handbook, International and Operational Law Department, Charlottesville, VA, 2009, pp. 10–13Google Scholar (hereinafter OPLAW HB) with US Department of the Army Field Manual 27–10, The Law of Land Warfare, Pentagon, Washington, D.C., 15 July 1976, Rules 41–44, available at: http://www.afsc.army.mil/gc/files/fm27-10.pdf (last visited 2 November 2012).

44 N. Melzer, above note 30, p. 365.

45 I. Henderson, above note 7, p. 168.

46 API, above note 3, Art. 57(2)(b); ICRC Study, above note 9, pp. 60–62; I. Henderson, above note 7, p. 235.

47 API, above note 3, Art. 57(2)(c); ICRC Study, above note 9, pp. 62–65.

48 I. Henderson, above note 7, p. 187; Solf, Waldemar A., ‘Protection of civilians against the effects of hostilities under customary international law and Protocol 1’, in American Journal of International Law and Policy, Vol. 80, No. 1, January 1986, p. 132Google Scholar.

49 ICRC Commentary, above note 14, paras. 2223–2225.

50 Ibid., para. 2226.

51 API, above note 3, Art. 57(3); ICRC Study, above note 9, pp. 65–67.

52 The US practice of developing and applying ROE is discussed in greater detail below.

53 US Department of Defense, Directive 2311.01E, DoD Law of War Program, Pentagon, Washington, D.C., 9 May 2006, p. 2, available at: http://www.dtic.mil/whs/directives/corres/pdf/231101e.pdf (last visited 2 November 2012).

54 Ibid.

55 This institution provides legal training to judge advocates and develops legal doctrine. See https://www.jagcnet.army.mil (last visited 1 November 2012).

56 OPLAW HB, above note 43, pp. 10–13.

57 Ibid., p. 10.

58 Ibid., p. 10, citing Hague Convention IV, above note 40, Art. 23.

59 Ibid., at 10.

60 Ibid., at 11.

61 Ibid.

62 Ibid., p. 12 (defined as ‘objects which by their nature, location, purpose or use, make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage’).

63 Ibid.

64 Ibid.

65 Land Warfare, above note 43, Rule 41 (citing the 1956 rules which provide that ‘loss of life and damage to property must not be out of proportion to the military advantage to be gained’).

66 OPLAW HB, above note 43, p. 12.

67 Ibid.

68 Ibid.

69 Ibid.

70 Ibid., p. 12, citing Hague IV, above note 40, Art. 23(e).

71 Ibid.

72 US Chairman of the Joint Chiefs of Staff, Instruction 3121.01B, Standing Rules of Engagement/Standing Rules for the Use of Force for US Forces, Pentagon, Washington, D.C., 13 June 2005Google Scholar (unclassified portion reprinted in OPLAW HB, above note 43, pp. 82–96).

73 US Department of Defense, Joint Publication 1-02, Dictionary of Military and Associated Terms (hereinafter DoD Terms), Pentagon, Washington, D.C., 15 August 2012, p. 473Google Scholar, available at: http://www.dtic.mil/doctrine/new_pubs/jp1_02.pdf (last visited 2 November 2012).

74 OPLAW HB, above note 43, p. 83.

75 Ibid. , pp. 73–74.

76 DoD Terms, above note 73, p. 538.

77 US Department of Defense, Joint Publication 3-60, Joint Targeting (hereinafter Joint Targeting), Pentagon, Washington, D.C., 12 April 2007, pp. E1-2Google Scholar, available at: www.aclu.org/files/dronefoia/dod/drone_dod_jp3_60.pdf (last visited 2 November 2012).

78 Ibid., p. E-4.

79 Ibid.

80 Ibid.

81 Ibid.

82 Ibid., p. G-1 (citing US Chairman of the Joint Chiefs of Staff, Manual 3160.01A, Joint Methodology for Estimating Collateral Damage for Conventional Weapons, Precision, Unguided, and Cluster (classified publication).

83 See, e.g., US Department of the Army, Field Manual 3-24, Counterinsurgency (hereinafter COIN Manual), Pentagon, Washington, D.C., 15 December 2006, p. D-2Google Scholar, available at: www.fas.org/irp/doddir/army/fm3-24.pdf (last visited 2 November 2012).

84 Joint Targeting, above note 77, p. G-1.

85 Ibid.; see also US Department of Defense, Joint Fires and Targeting Handbook (hereinafter Targeting HB), Pentagon, Washington, D.C., 19 October 2007, pp. III-77–78Google Scholar, available at: http://www.dtic.mil/doctrine/doctrine/jwfc_pam.htm (last visited 2 November 2012).

86 Joint Targeting, above note 77, p. II-10.

87 Ibid., p. I-6.

88 Ibid., p. I-7. For classification reasons, dynamic or hasty targeting is not discussed herein, but the legal obligations remain unchanged.

89 Joint Targeting, above note 77, p. E-3; Targeting HB, above note 85, p. III-77.

90 For additional doctrine, please see US Army Tactics, Techniques, and Procedures, Civilian Casualty Mitigation, Pentagon, Washington, D.C., 18 July 2012Google Scholar, available at: http://www.fas.org/irp/doddir/army/attp3-37-31.pdf (last visited 2 November 2012). (The pamphlet emphasizes the need to mitigate civilian casualties in all combat actions and in all combat environments. It adds little to the targeting matters discussed herein, but the general expressions of US Army policy may prove useful for practitioners seeking to evaluate US state practice.)

91 The Holy Bible, Genesis, 18:20–33.

92 API, above note 3, Arts. 51(5)(b) and 57(2)(a)(iii) and (b).

93 API, above note 3, Art. 85(3)(b) and (c).

94 Rome Statute of the International Criminal Court (last amended 2010) (hereinafter Rome Statute), 17 July 1998, 2187 UNTS 90, Art. 8(2)(b)(iv), available at: http://www.unhcr.org/refworld/docid/3ae6b3a84.html (last visited 2 November 2012).

95 I. Henderson, above note 7, p. 247.

96 Fenrick, William J., ‘The rule of proportionality and Protocol I in conventional warfare’, in Military Law Review, Vol. 98, No. 1, Fall 1982, p. 95Google Scholar; A. P. V. Rogers, above note 32, p. 17.

97 Instructions for the Government of Armies of the United States in the Field, General Orders No. 100, 24 April 1863, Arts 15 and 22, available at: http://www.loc.gov/rr/frd/Military_Law/pdf/Instructions-gov-armies.pdf (last visited 2 November 2012). Compare [Article 15] ‘Military necessity admits of all direct destruction of life or limb of armed enemies, and of other persons whose destruction is incidentally unavoidable in the armed contests of the war’ with [Article 22] ‘Nevertheless, as civilization has advanced during the last centuries … [t]he principle has been more and more acknowledged that the unarmed citizen is to be spared in person, property, and honor as much as the exigencies of war will admit’.

98 Declaration Renouncing the Use, in Time of War, of Explosive Projectiles under 400 Grammes Weight, 138 Consol. TS 297, 11 December 1868, available at: http://www.icrc.org/IHL.NSF/ (last visited 2 November 2012).

99 Hague IV, above note 40, Art. 23.

100 W. F. Fenrick, above note 96, p. 96; N. Melzer, above note 30, pp. 357–358.

101 Y. Tanaka and M. B Young, above note 5, p. 78.

102 Rules for Air Warfare Drafted by a Commission of Jurist at The Hague, December 1922 to February 1923, Art. 24(3) available at: http://www.icrc.org/ihl/INTRO/275?OpenDocument (last visited 2 November 2012).

103 Ibid., Art. 24(4).

104 Draft Rules for the Limitation of the Dangers Incurred by the Civilian Population in Time of War, 1956, available at: http://www.icrc.org/ihl/INTRO/420?OpenDocument (last visited 2 November 2012).

105 Ibid., Art. 8.

106 Ibid., Art. 9.

107 I. Henderson, above note 7, p. 247.

108 APII, above note 22, preamble and Art. 13(2).

109 ICRC Study, above note 9, Rule 14 p. 46 (‘Launching an attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and directly military advantage anticipated, is prohibited’).

110 DoD Report, above note 35, p. 691. For recognition of US practice, see LOW DB, above note 6, pp. 142–143; DoD Report, above note 35, pp. 697–698 (‘The principle of proportionality acknowledges the unfortunate inevitability of collateral civilian casualties and collateral damage to civilian objects when non-combatants and civilian objects are mingled with combatants and targets, even with reasonable efforts by the parties to a conflict to minimize collateral injury and damage’).

111 ICRC Study, above note 9, pp. 49–50.

112 API, above note 3, Art. 85.

113 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 (hereinafter CCW), 19 ILM 1523, 10 October 1980, available at: http://www.icrc.org/eng/resources/documents/publication/p0811.htm (last visited 2 November 2012).

114 Protocol on Prohibitions or Restrictions on the Use of Mines, Booby-Traps and Other Devices (Protocol II to CCW), 10 October 1980, Art. 3(3), available at: http://www.icrc.org/IHL.NSF/ (last visited 2 November 2012).

115 Protocol II to CCW, as amended 3 May 1996, Art. 3(8)(c), available at: http://www.icrc.org/IHL.NSF/ (last visited 2 November 2012) (‘Indiscriminate use is any placement of such weapons … which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated’).

116 Ibid.

117 ICRC Commentary, above note 14.

118 Ibid., p. 624, para. 1979.

119 Ibid., p. 624, para. 1979 and pp. 683–684, para. 2208.

120 Ibid., pp. 683–684, paras. 2208–2210.

121 Ibid.

122 Ibid., p. 626, para. 1980.

123 ICRC Study, above note 9, Vol. II, Practice Relating to Rule 14.

124 HPCR Commentary, above note 29. See also HPCR, Manual on International Law Applicable to Air and Missile Warfare, 15 May 2009, available at: http://www.ihlresearch.org/amw/manual/ (last visited 2 November 2012).

125 HPCR Commentary, above note 29, pp. 91–92.

126 Ibid., p. 92.

127 Ibid.

128 Ibid.

129 Ibid., p. 91.

130 Ibid.

131 International Human Rights and Conflict Resolution Clinic (Stanford Law School) and Global Justice Clinic (NYU School of Law), Living under Drones: Death, Injury, and Trauma to Civilians from US Drone Practices in Pakistan, September 2006, pg. vii, available at: http://livingunderdrones.org/report/ (last visited 2 November 2012).

132 HPCR Commentary, above note 29, p. 94.

133 Parks, W. Hays, ‘Air war and the law of war’, in Air Force Law Review, Vol. 32, No. 1, 1990, p. 175Google Scholar.

134 Garner, Bryan A. (ed.), Black's Law Dictionary, Thompson West, St Paul, MI, 2009Google Scholar (‘[O]bjective standard. A legal standard that is based on conduct and perceptions external to a particular person. [S]ubjective standard. A legal standard that is peculiar to a particular person and based on the person's individual views and experiences’).

135 Green, Leslie C., The Contemporary Law of Armed Conflict, Manchester University Press, Manchester, 2008, p. 391Google Scholar (‘there is no definition as to what is excessive’); D. Fleck, above note 1, pp. 178–179 (‘the principle of proportionality … remains loosely defined and is subject to subjective assessment and balancing’); I. Henderson, above note 7, pp. 221–226 and 247; N. Melzer, above note 30, pp. 359–363; Gardam, Judith, Necessity, Proportionality and the Use of Force by States, Cambridge University Press, Cambridge 2004, p. 98CrossRefGoogle Scholar (classifying proportionality assessment as ‘imprecise’).

136 L. C. Green, above note 135, p. 391.

137 N. Melzer, above note 30, p. 361; Y. Dinstein, above note 34, p. 122; J. Gardam, above note 135, pp. 105–106.

138 D. Fleck, above note 1, pp. 178–179 (The rule ‘is subject to subjective assessment and balancing … [and] the actors enjoy a considerable margin of appreciation.’); Y. Tanaka and M. B. Young, above note 5, p. 225 (‘The formulation of the proportionality rule incorporates a margin of appreciation in favor of military commanders’).

139 A. P. V. Rogers, above note 32, p. 110; See also Y. Dinstein, above note 34, p. 122 (‘Undeniably, the attacker must act in good faith and not simply turn a blind eye on the facts of the situation; on the contrary, he is obliged to evaluate all available information’); Y. Tanaka and M. B. Young, above note 5, p. 225.

140 D. Fleck, above note 1, p. 179 (‘Objective standards for the appraisal of expected collateral damage and the intended military advantage are virtually non-existent’); Y. Dinstein, above note 34, p. 122 (‘There is no objective possibility of quantifying the factors of the equation, and the process necessarily contains a large subjective element’).

141 Y. Dinstein, above note 34, p. 122.

142 I. Henderson, above note 7, p. 222.

143 Ibid., p. 223.

144 See e.g., L. C. Green, above note 135, p. 391 (‘Although the decision as to proportionality tends to be subjective, it must be made in good faith and may in fact come to be measured and held excessive in a subsequent war crimes trial’).

145 Because this work focuses on the jus in bello proportionality rule in the conduct of hostilities, the International Court of Justice's advisory opinion, Legality of the Threat or Use of Nuclear Weapons, 1996 ICJ Rep. 226, will not be discussed.

146 International Criminal Tribunal for the Former Yugoslavia (ICTY), Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign Against the Federal Republic of Yugoslavia, 39 ILM 1257, November 2000, also available at: http://www.icty.org/x/file/Press/nato061300.pdf (last visited 2 November 2012).

147 Ibid., paras. 2 and 54.

148 Ibid., paras. 49–50.

149 Ibid., para. 50 (‘Although there will be room for argument in close cases, there will be many cases where reasonable military commanders will agree that injury to non-combatants or the damage to civilian objects was clearly disproportionate to the military advantage gained’).

150 Ibid., paras. 71–72.

151 Ibid.

152 Ibid.

153 Ibid., para. 77 (‘Assuming the station was a legitimate objective, the civilian casualties were unfortunately high but do not appear to be clearly disproportionate’).

154 Ibid.

155 Ibid., para. 21(‘The use of the word “clearly” [in the Rome Statute for Article 8(b)(iv)] ensures that criminal responsibility would be entailed only in cases where excessiveness of the incidental damage was obvious’).

156 ICTY, The Prosecutor v. Stanislav Galic, Case No. IT-98-29-T, 43 ILM 794 Judgment (Trial Chamber 1), 5 December 2003, available at: http://www.icty.org/x/cases/galic/tjug/en/gal-tj031205e.pdf (last visited 2 November 2012). For a case summary, see Gail, Liza, ‘Introductory Note to ICTY: Prosecutor v. Galić’, in International Legal Materials, Vol. 43, No. 4, July 2004, pp. 789–793Google Scholar.

157 Ibid., para. 58.

158 Ibid., para. 59.

159 Israel High Court of Justice, Public Committee against Torture in Israel v. Israel, HCJ 769/02, 46 ILM 375, Judgment, 11 December 2005, available at: http://elyon1.court.gov.il/Files_ENG/02/690/007/A34/02007690.A34.pdf (last visited 2 November 2012).

160 Ibid.

161 Ibid., para. 46.

162 Ibid., para. 45.

163 Ibid., para. 57.

164 Ibid., para. 46.

165 Ibid.

166 Ibid., Concurring Opinion, para. 5 (Rivlin, J.).

167 Rome Statute, above note 94, Art. 8(2)(b)(iv) (emphasis added).

168 Rome Statute, above note 94, Art. 10; ICRC Study, above note 9, p. 577.

169 Proposal Submitted by the USA to the Preparatory Committee on the Establishment of an International Criminal Court, UN Doc. A/AC.249/1998/DP.11, 2 April 1999.

170 Ibid., p. 13.

171 Public Committee, above note 159, para. 46.

172 For a discussion of the jus ad bellum and targeting, see N. Melzer, above note 30, pp. 51–54, or J. Gardam, above note 135, Chaps. 5 and 6.

173 Lao Tzu, The Tao Te Ching, verse 30, available at: http://ebooks.adelaide.edu.au/l/lao/tzu/l2988t/ (last visited 2 November 2012).

174 COIN Manual, above note 83, para. 159.

175 Ibid., paras. 5 and 100–103.

176 Ibid., para. 7–30.

177 Ibid., para. 7–32.

178 Ibid.

179 Ibid.

180 Ibid.

181 Ibid., para. 7–36.

182 Ibid.

183 Ibid., p. E-1.

184 Ibid.

185 Ibid., para. 7–37.

186 Ibid.

187 Ibid., p. E-2.

188 I. Henderson, above note 7, p. 223.

189 Cohen, Amichai and Shany, Yuval, ‘A development of modest proportions – the application of the principle of proportionality in the targeted killings case’, in the Journal of International Criminal Justice, Vol. 5, No. 2, May 2007, p. 319CrossRefGoogle Scholar.

190 API, above note 3, Art. 85.

191 Rome Statute, above note 94, Art. 8(b)(iv).

192 While the anticipated military advantage in an attack will always vary in light of prevailing circumstances at the time based on tactical, operational, and strategic objectives, national militaries may find it useful to establish objective guidelines concerning what amount of civilian death, injury, or destruction would generally be marginal, moderate, and substantial (e.g., 0–1 anticipated civilian casualties is marginal, 2–4 is moderate, and 5+ is substantial).

193 ICRC Commentary, above note 14, p. 626, para. 1980.

194 Public Committee, above note 158; Concurring Opinion, para. 5. (Rivlin, J.).

195 HPCR Commentary, above note 29, p. 92.

196 Myrer, Anton, Once an Eagle, HarperCollins, New York, 1968, p. 1288Google Scholar.

197 Public Committee, above note 159, para. 46.

198 These steps are extracted from API Art. 48–57; see also, I. Henderson, above note 7, pp. 237–238; N. Melzer, above note 30, pp. 419, 427.

199 API, above note 3, Arts 48, 50, 51, 52, and 57(2)(a)(i).

200 API, above note 3, Art. 52(2) (‘In so far as objects are concerned, military objectives are limited to those objects which by their nature, location, purpose or use make an effective contribution to military action and whose total or partial destruction, capture, or neutralization, in the circumstances ruling at the time, offers a definite military advantage’).

201 For a concise discussion on the rules governing the targeting of civilians who may be part of an irregular armed group, see HPCR Commentary, above note 29, pp. 117–124. See also, ICRC, Interpretive Guidance on the Notion of Direct Participation in Hostilities Under International Humanitarian Law (2008)Google Scholar, above note 25.

202 HPCR Commentary, above note 29, p. 49 (Definite ‘exclude[s] advantage which is merely potential, speculative, or indeterminate’).

203 API, above note 3, Arts 48, 51(2), 52, and 57(2)(a)(i).

204 API, above note 3, Arts 57(1) and 57(a)(2)(ii).

205 Civilian Casualty Mitigation, above note 90, para. 2–54 (Rules of Engagement Considerations) this third step is arguably lex feranda); see Schmitt, Michael N., ‘Book review: targeted killing in international law’, in American Journal of International Law, Vol. 103, No. 4, October 2009, pp. 817–818Google Scholar. However, the non-international conflict of counterinsurgency warfare requires this consideration as a matter of US state practice. HPCR Commentary, above note 29, pp. 44 and 91. (For definitions, concrete and direct ‘refers to military advantage that is clearly identifiable and, in many cases, quantifiable … it cannot be based merely on hope or speculation’, and military advantage ‘means those benefits of a military nature that result from an attack … relat[ing] to the attack considered as whole and not merely to isolated or particular parts of the attack’.)

206 API, above note 3, Art. 57.

207 ICRC Commentary, above note 14, p. 684, para. 2212. HPCR Commentary, above note 29, p. 38 (Feasible ‘means that which is practicable or practically possible, taking into account all circumstances prevailing at the time, including humanitarian and military considerations’).

208 API, above note 3, Arts 51(5)(b) and 57(2)(a)(iii).

209 HPCR Commentary, above note 29, p. 91.

210 Civilian Casualty Mitigation, above note 90, para. 2–33.

211 API, above note 3, Art. 57(2)(b).

212 API, above note 3, Arts 48 and 51(4)(a).

213 The Holy Qu'ran, verse 17:31.