1. U.N. Charter, arts. 2(4), 42, 51.

2. The Responsibility to Protect: Report of the International Commission on Intervention and State Sovereignty (International Development Research Centre, 2001). These aspirations set out by the International Commission on Intervention and State Sovereignty (ICISS) were significantly constrained in the subsequent outcome document of the 2005 World Summit. See 2005 World Summit Outcome, U.N. Doc. A/60/L1 (Sept. 15, 2005). For discussion, see Bellamy, Alex J., Whither the Responsibility to Protect? Humanitarian Intervention and the 2005 World Summit, 20 Ethics & Int'l Affs. 143 (2006)Google Scholar.

3. See Charles Beitz, Nonintervention and Communal Integrity, 9 Phil. & Pub. Affs. 385 (1980); Ken Booth, Military Intervention: Duty and Prudence, in Military Intervention in European Conflicts 56 (Lawrence Freedman ed., 1994). See also Valentino, Benjamin A., The True Costs of Humanitarian Intervention: The Hard Truth About a Noble Notion, 90 Foreign Affs. 60 (2011)Google Scholar.

4. Human Rights Watch, Civilian Deaths in the NATO Air Campaign – The Crisis in Kosovo (archived Nov. 2016), https://www.hrw.org/reports/2000/nato/Natbm200-01.htm; Civilian Deaths “Necessary Price”, BBC News (May 31, 1999), http://news.bbc.co.uk/1/hi/world/europe/357355.stm; Richard Norton-Taylor, How the Serb Army Escaped Nato, Guardian (Mar. 9, 2000), https://www.theguardian.com/world/2000/mar/09/balkans1.

5. Human Rights Watch, Unacknowledged Deaths: Civilian Casualties in NATO's Air Campaign in Libya (May 14, 2012), https://www.hrw.org/report/2012/05/13/unacknowledged-deaths/civilian-casualties-natos-air-campaign-libya; C. J. Chivers & Eric Schmitt, In Strikes on Libya by NATO, an Unspoken Civilian Toll, N.Y. Times (Dec. 17, 2011), https://www.nytimes.com/2011/12/18/world/africa/scores-of-unintended-casualties-in-nato-war-in-libya.html; Dominic Tierney, The Legacy of Obama's ‘Worst Mistake’, Atlantic (Apr. 15, 2016), https://www.theatlantic.com/international/archive/2016/04/obamas-worst-mistake-libya/478461/.

6. For discussion, see Ivan Shearer, Rules of Conduct During Humanitarian Intervention, in Legal and Ethical Lessons of NATO's Kosovo Campaign, International Law Studies 78, 82 (Andru E. Wall ed., 2002).

7. For philosophical debate on the relationship between morality and law in war, see McMahan, Jeff, The Ethics of Killing in War, 114 Ethics 693 (2004)CrossRefGoogle Scholar; McMahan, The Morality of War and the Law of War, in Just and Unjust Warriors: The Moral and Legal Status of Soldiers 19, 27–28 (David Rodin & Henry Shue eds., 2008); McMahan, The Laws of War, in The Philosophy of International Law 493 (Samantha Besson & John Tasioulas eds., 2010); Adil Haque, Law and Morality at War (2017); Victor Tadros, To Do, To Die, To Reason Why (2020), ch. 12. See also Henry Shue, Do We Need a “Morality of War”?, in Just and Unjust Warriors 87 (David Rodin & Henry Shue eds., 2010); Henry Shue, Laws of War, in The Philosophy of International Law 511, 519–522 (Samantha Besson & John Tasioulas eds., 2010); Dill, Janina, Should International Law Ensure the Moral Acceptability of War?, 26 Leiden J. Int'l L. 253 (2013)CrossRefGoogle Scholar; Janina Dill & Henry Shue, Limiting the Killing in War: Military Necessity and the St. Petersburg Assumption, 26 Ethics & Int'l Affs. 311 (2012). For recent articulations of the broader view that morality is relevant to how we should interpret and apply (international) law, see Ezequiel H. Monti, On the Moral Impact Theory of Law, 42 Oxford J. Legal Stud. 298 (2022); Steven Ratner, David Luban, Carmen Pavel, Jiewuh Song & James Stewart, International Law and Theories of Global Justice, 114 Proc. Am. Soc'y Int'l L. 1 (2020).

8. Exceptions include James Pattison, The Ethics of “Responsibility While Protecting”: Brazil, the Responsibility to Protect, and the Restrictive Approach to Humanitarian Intervention, in Brazil as a Rising Power: Intervention Norms and the Contestation of Global Order 104 (Kai Michael Kenkel & Philip Cunliffe eds., 2016); Pattison, Humanitarian Intervention, the Responsibility to Protect and Jus in Bello, 1 Glob. Resp. Protect 364 (2009); Pattison, Humanitarian Intervention and International Law: The Moral Importance of an Intervener's Legal Status, 10 Critical Rev. Int'l Soc. & Pol. Phil. 301 (2007).

9. For example, David Rodin, War and Self-Defense (2002); Simon Caney, Justice Beyond Borders (2005), chs. 6, 7; Jeff McMahan, Killing in War (2009); Cécile Fabre, Cosmopolitan War (2012); Helen Frowe, Defensive Killing (2014); Tadros, supra note 7.

10. But it has roots in existing international law, in the form of the Genocide Convention, the Geneva Conventions, and their Additional Protocols. Crimes against humanity are spelled out in the Rome Statute; they do not have their own designated convention or treaty, though specific elements (such as torture and slavery) have their own conventions. So, states have legal obligations through other treaties and conventions to prevent the same crimes that the “responsibility to protect” seeks to prevent.

11. For example, some people have argued that UN Article 2(4) can be interpreted to support the use of force for humanitarian purposes. See, e.g., Fernando Tesón, Humanitarian Intervention: An Inquiry into Law and Morality (1997). See also Greenwood, Christopher, International Law and the NATO Intervention in Kosovo, 49 Int'l & Compar. L. Q. 926 (2000)Google Scholar. For critical discussion, see Michael Byers & Simon Chesterman, Changing the Rules About Rules? Unilateral Humanitarian Intervention and the Future of International Law, in Humanitarian Intervention: Ethical, Legal, and Political Dilemmas 177 (J. L. Holzgrefe & Robert O. Keohane eds., 2003). According to the Australian Red Cross, the principle of the “responsibility to protect” “does allow for the use of force under Chapter VII of the UN Charter for the protection of populations vulnerable to, or suffering from genocide, crimes against humanity, war crimes and ethnic cleansing.” See Red Cross Australia, International Humanitarian Law and the Responsibility to Protect: A Handbook (2001).

12. For discussion illustrating revisionism's moral appeal in the context of AHI, see McMahan, Jeff, Proportionality and Just Cause: A Comment on Kamm, 11 J. Moral Phil. 428 (2014)CrossRefGoogle Scholar; McMahan, War Crimes and Immoral Action in War, in The Constitution of Criminal Law 151, 178 (Antony Duff et al. eds., 2013); McMahan, Proportionality and Necessity in Jus in Bello, in The Oxford Handbook of the Ethics of War 418, §3 (Seth Lazar & Helen Frowe eds., 2017); McMahan, supra note 9, at 107.

13. The one exception is harms for which there is a lesser-evil justification.

14. For discussion, see Geert De Baere, Anna-Luise Chané & Jan Wouters, International Courts as Keepers of the Rule of Law: Achievements, Challenges, and Opportunities, 48 N.Y.U. J. Int'l L. & Pol. 715 (2016).

15. The main instruments of IHL are the Geneva Conventions of 1949, which primarily protect combatants who are hors de combat, and the Additional Protocols of 1977, which strengthen the protection of civilian victims of international and noninternational armed conflicts and constrain the ways in which wars are fought. Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I) (1977), Preamble. For discussion of IHL's main principles, see Bassiouni, M. Cherif, The Normative Framework of International Humanitarian Law: Overlaps, Gaps, and Ambiguities, 8 Transnat'l L. & Contemp. Probs. 199 (1999)Google Scholar; 1 Jean-Marie Henckaerts & Louise Doswald-Beck, Customary International Humanitarian Law: Rules (2005); Documents on the Laws of War (Adam Roberts & Richard Guelff eds., 3d ed. 2000).

16. For discussion and defenses of the conventional principle of distinction, see Haque, supra note 7; Seth Lazar, Sparing Civilians (2016).

17. Combatants “shall at all times distinguish between [civilians or] civilian objects and military objectives and accordingly shall direct their operations only against military objectives.” Protocol I art. 48. See also Henckaerts & Doswald-Beck, supra note 15, at 3.

18. Protocol I, 1125 U.N.T.S. 3, arts. 43 (2), 44; 1 International Committee of the Red Cross, Customary International Humanitarian Law (2009), at II, 384.

19. Nothing in my argument hangs on whether we interpret the legal equality of combatants as symmetrical legal permissions to fight or as symmetrical legal prohibitions on ways of fighting and symmetrical legal immunities from criminal prosecution for certain acts. For discussion, see Haque, supra note 7, at 23–34. For justifications for using the language of permissions, see David Rodin, Morality and Law in War, in The Changing Character of War 446, 455 (Hew Strachan & Sibyelle Scheipers eds., 2011). See also Jeremy Waldron, Torture, Terror, Trade-offs (2010), at 107, 109–111. Waldron has more recently endorsed Haque's view as the more accurate one (Waldron, , Responses to Zedner, Haque and Mendus, 8 Crim. L. & Phil. 135, 137 (2014)Google Scholar).

20. For discussion and defense, see Robert D. Sloane, The Cost of Conflation: Preserving the Dualism of Jus ad Bellum and Bello, Jus in in the Contemporary Law of War, 34 Yale J. Int'l L. 48 (2008)Google Scholar. See also Luban, David, Just War Theory and the Laws of War as Nonidentical Twins, 31 Ethics & Int'l Affs. 433 (2017)Google Scholar.

21. See, e.g., Martin Shaw, The New Western Way of War: Risk-Transfer War and Its Crisis in Iraq (2005).

22. For discussion, see McMahan, Jeff, The Just Distribution of Harm Between Combatants and Noncombatants, 38 Phil. & Pub. Affs. 342 (2010)Google Scholar; Leveringhaus, Alex, The Moral Status of Combatants During Military Humanitarian Intervention, 24 Utilitas 237 (2012)CrossRefGoogle Scholar.

23. While genocide and war crimes have been codified in dedicated treaties of international law, this is not yet the case for crimes against humanity. However, similarly to the prohibition of genocide, the prohibition of crimes against humanity is considered a peremptory norm of international law, which applies to all states and from which no derogation is permitted (see Article 7 of the Rome Statute).

24. For discussion, see McMahan, Jeff, Individual Liability in War: A Response to Fabre, Leveringhaus, and Tadros, 24 Utilitas 288, 291 (2012)CrossRefGoogle Scholar; Caney, supra note 9, at 194; Leveringhaus, supra note 22.

25. Christopher Kutz argues that this is McMahanian revisionism's main mistake. See Kutz, Fearful Symmetry, in Just and Unjust Warriors: The Moral and Legal Status of Soldiers 69, 75 (David Rodin & Henry Shue eds., 2008).

26. This also applies to situations of armed conflict in which one party's goal is clearly just and the other's clearly unjust. I make no assumption that the argument must be limited to AHI. The claim in question may be just as problematic in other types of armed conflict.

27. For discussion, see Bruce Cronin, Bugsplat: The Politics of Collateral Damage in Western Armed Conflicts (2018).

28. As stated earlier, the claim here is not that there is a categorical difference between just AHI and other just wars, such as just wars of self-defense against unjust aggression. The assumption is simply that the more direct the connection between the justness of a war aim and the justness of the threats posed by individuals, the more pronounced the Problem of Unreliable Proxies.

29. For discussion, see David Scheffer, All the Missing Souls (2012), ch. 14. See also Ronald Dworkin's discussion of international legitimacy in his A New Philosophy for International Law, 41 Phil. & Pub. Affs. 2 (2013). For discussion concerning the jus post bellum, see Cécile Fabre's proposal for an international compensation fund in her Cosmopolitan Peace (2016), at 152–170.

30. For example, Jeff McMahan, The Prevention of Unjust Wars, in Reading Walzer 233 (Yitzhak Benbaji & Naomi Sussman eds., 2014); see also Adam Thomas Betz, Epistemic Authority, Sovereignty, and Selective Conscientious Objection: A Critical Revision of McMahan's “Jus Ad Bellum” Court, 44 Soc. Theory & Prac. 507 (2018).

31. For accounts that defend a categorized approach to liability in line with what I describe as proximate protection, see Bradley Jay Strawser, Walking the Tightrope of Just War, 71 Analysis 533, 540–542 (2011), and Revisionist Just War Theory and the Real World: A Cautiously Optimistic Proposal, in Routledge Handbook of Ethics and War: Just War in the 21st Century 76 (Fritz Allhoff, Adam Henschke & Nick Evans eds., 2013); Gerhard Øverland, Killing Soldiers, 20 Ethics & Int'l Affs. 455 (2006). For more extensive proposals about how the LOAC might be brought into greater congruence with morality, see Tadros, supra note 7, ch. 12; Haque, supra note 7; Janina Dill, Towards a Moral Division of Labour Between IHL and IHRL During the Conduct of Hostilities, in Law Applicable to Armed Conflict (Ziv Bohrer, Janina Dill & Helen Duffy eds., 2020). In contrast to the present inquiry, these accounts are concerned with the merits of legal revisionism in general.

32. In principle, the PPP has moral appeal whenever its margin of error regarding the protection of the innocent would be smaller than that of the traditional principle of the legal equality of combatants. I take it that all just wars, by definition, are justified on the grounds that they seek to protect basic human rights. Hence, in theory, the PPP may also apply in mandated rescue missions or cases in which international law permits the resort to force (that is, with UN Security Council approval). Since the PPP is not a proposal for legal reform, but part of a dialectical strategy to crystalize precisely what stands in the way of the justice criterion, we can set aside hypothetical questions about the PPP's applicability in different legal contexts. I am grateful to an anonymous reviewer for pressing me to clarify this.

33. Most revisionists assume the former; for a defense of the latter view, see Tadros, supra note 7, ch. 12.

34. For example, McMahan, supra note 22, and McMahan, The Morality of War and the Law of War, supra note 7.

35. As noted earlier, though I am sympathetic to the project of legal revisionism, it is not my aim to defend this here.

36. I do not take this principle to bear on the treatment of noncombatants engaged in the perpetration of atrocity crimes. While I assume that these individuals are morally liable to defensive harm, I do not discuss what the law should say about them. I suspect that the existing legal provision for a permission to attack civilians directly participating in hostilities may plausibly extend to civilian perpetrators of atrocity crimes. For arguments that support the moral case for civilian liability, see Helen Frowe, Civilian Liability, 129 Ethics 625 (2019); Frowe, Defensive Killing (2014); Frowe, Self-Defence and the Principle of Non-Combatant Immunity, 8 J. Moral Phil. 530 (2011).

37. For discussion, see McMahan, supra note 9, 188.

38. For discussion, see Gabriella Blum, The Laws of War and the “Lesser Evil”, 103 Proc. Am. Soc'y Int'l L. 274 (2009).

39. There may be cases in AHI in which unjust combatants morally permissibly defend fellow unjust combatants. But associative obligations to fellow unjust combatants are morally outweighed by duties not to kill just combatants preventing atrocity crimes, and would themselves need to be justified.

40. Gerhard Øverland, High-Fliers: Who Should Bear the Risk of Humanitarian Intervention?, in New Wars and New Solders: Military Ethics in the Contemporary World 69, 70 (Jessica Wolfendale & Paolo Tripodi eds., 2011).

41. Henry Shue, Laws of War, Morality and International Politics: Compliance, Stringency, and Limits, in Fighting Hurt: Rule and Exception in Torture and War 469, 485 (2016).

42. For discussion of this and related methodological issues, see Seth Lazar, Method and Morality in War, in The Oxford Handbook of Ethics and War 19 (Seth Lazar & Helen Frowe eds., 2015); Seth Lazar & Laura Valentini, Proxy Battles in the Ethics of War, in 3 Oxford Studies in Political Philosophy (David Sobel, Peter Vallentyne & Steven Wall eds., 2017); Linda Eggert, Rights and Rules: Revisionism, Contractarianism, and the Laws of War, Law & Phil. (2022), at §V.

43. Haque, supra note 7, at 48–49.

44. 1880 Oxford Manual, Preamble, cited in Henry Shue, Laws of War, Morality, and International Politics: Compliance, Stringency, and Limits, 26 Leiden J. Int'l L. 271 (2013); Shue, Fighting Hurt: Rule and Exception in Torture and War (2016), at 467–493.

45. See Dill & Shue, supra note 7; Shue, supra note 44, at 452, 454, 467 n.30; Haque, supra note 7, at 41.

46. See David Luban, Human Rights Thinking and the Laws of War, in Theoretical Boundaries of Human Rights and Armed Conflict 52 (Jens David Ohlin ed., 2016); Dill & Shue, supra note 7.

47. Declaration Renouncing the Use, in Time of War, of Explosive Projectiles under 400 Grammes Weight, Saint Petersburg, Nov. 29 / Dec. 11, 1868, cited in Dill & Shue, supra note 7, at 455; Dill & Shue, supra note 7, at 311, 319; Haque, supra note 7, at 20.

48. Dill & Shue, supra note 7, at 448, 454, 467. For discussion, see Haque, supra note 7, at 38–40. One might hold that the laws of war should neither aim to prevent merely harm in general nor merely unjust harm; rather, they should both prevent wrongdoing and reduce harm in general. For example, Victor Tadros argues that if the law could, through deterrence, prevent many people from posing unjust threats to others in the first place, it should do so. The harms the law should seek to prevent thus include those that it would be permissible to inflict on unjust combatants. See Tadros, supra note 7, at 279–280. This seems to me completely right. Indeed, that {deterring unjust threats} is preferable to {unjust threats being posed and then harmfully averted} is consistent with the claim that, once a war is underway and unjust threats are being posed, preventing unjust harms is, morally speaking, more morally urgent than preventing harm in general. Far from denying that deterring people from posing unjust threats in the first place would be preferable, the PPP's prohibition on attacking just combatants is itself meant to deter unjust combatants from posing unjust threats (on which more below). The PPP just presumes that, once a war is underway, the next best thing is to prioritize the prevention and reduction of unjust harms. Thanks to Victor Tadros for pressing me on this.

49. Tony Pfaff, Peacekeeping and the Just War Tradition (2000), at 2 (emphasis added); also discussed in James Pattison, Humanitarian Intervention and the Responsibility to Protect: Who Should Intervene? (2010), at 106–107. While Pfaff's argument is primarily about the use of force in peace operations, Pattison suggests that, like in peace operations, AHI call for the use of “the least force” possible.

50. For discussion, see Rodin, supra note 19, at 455.

51. 1977 Geneva Protocol I Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts, in Documents in the Laws of War 416 (Adam Roberts & Richard Guelff eds., 1982) (emphasis added).

52. Pattison, supra note 49, at 104–109. See also Alex J. Bellamy, Motives, Outcomes, Intent and the Legitimacy of Humanitarian Intervention, 3 J. Mil. Ethics 216, 229 (2004); Eric A. Heinze, Humanitarian Intervention: Morality and International Law on Intolerable Violations of Human Rights, 8 Int'l J. Hum. Rts. 471 (2004); George Lucas, The Role of the “International Community” in Just War Tradition—Confronting the Challenges of Humanitarian Intervention and Preemptive War, 2 J. Mil. Ethics 122 (2003).

53. Pattison, supra note 49, at 100 (original emphasis).

54. For instance, McMahan, supra note 9, at 61, 148–149; McMahan, Duty, Obedience, Desert, and Proportionality in War: A Response, 122 Ethics 135, 138 (2011); Shue, supra note 41, at 473; Shue, Do We Need a ‘Morality of War’, in Fighting Hurt: Rule and Exception in Torture and War 401, 414 (2016); Shue, Laws of War, Morality, and International Politics, in Fighting Hurt 469, 476 (2016); Shue with Janina Dill, Limiting the Killing in War, in Fighting Hurt 447, 459, 463 (2016); Shue, Laws of War, in Fighting Hurt 429, 439–440 (2016).

55. McMahan, The Laws of War, supra note 7; McMahan, The Morality of War and the Law of War, supra note 7; McMahan, supra note 9, at 190–191.

56. For example, McMahan, supra note 9, at 148–149; see also McMahan, supra note 54, at 138.

57. Shue, Laws of War, Morality, and International Politics, supra note 54, at 484–486; Jeremy Waldron, Deep Morality and the Laws of War, in The Oxford Handbook of Ethics and War 80 (Seth Lazar & Helen Frowe eds., 2018).

58. For discussion of the effectiveness of holding political leaders criminally accountable for human rights violations, and an argument that such prosecutions may diminish human rights violations in the future, see Kathryn Sikkink & Hun Joon Kim, The Justice Cascade: The Origins and Effectiveness of Prosecutions of Human Rights Violations, 9 Ann. Rev. L. & Soc. Sci. 269 (2013).

59. Monica Hakimi, The Work of International Law, 58 Harv. Int'l L. J. 1 (2017); Ian Hurd, How to Do Things with International Law (2017).

60. Jeff McMahan, The Ethics of Killing in War, supra note 7; for discussion, see also Haque, supra note 7.

61. For discussion, see Seth Lazar, Skepticism About Jus Post Bellum, in Morality, Jus Post Bellum, and International Law 204 (Larry May & Andrew Forcehimes eds., 2012).

62. See the 2018 UN Human Rights Committee's General Comment 36 on the right to life, which includes the statement that “States parties engaged in acts of aggression as defined in international law, resulting in deprivation of life, violate ipso facto article 6 of the Covenant.” This has fueled debates about the relationship between human rights and the jus ad bellum. See United Nations Human Rights Committee (HRC), General comment No. 36 (2018) on Article 6 of the International Covenant on Civil and Political Rights, on the Right to Life, U.N. Doc. CCPR/C/GC/36, Oct. 30, 2018 (GC 36). For discussion, see Dapo Akande & Katie A. Johnston, Implications of the Diversity of the Rules on the Use of Force for Change in the Law, 32 Eur. J. Int'l L. 679 (2021). For discussion of how the criminalization of aggression might affect the possibility of resort to force to protect human rights, see Kevin Jon Heller, The Illegality of ‘Genuine’ Unilateral Humanitarian Intervention, 32 Eur. J. Int'l L. 613 (2021). On Heller's view, AHI do not generate an exception to the prohibition on the use of force, because even “genuine” humanitarian interventions might violate the prohibition of the use of force and count as crimes of aggression as specified by the Rome Statute of the ICC.

63. The position that these interventions were illegal is based on standard interpretations of Articles 2(4) and 2(7) of the UN Charter. See, e.g., Nigel Rodley, Humanitarian Intervention, in The Oxford Handbook of the Use of Force in International Law 775 (Larry May & Andrew Forcehimes eds., 2015). For discussion, see Allen Buchanan, From Nuremberg to Kosovo: The Morality of Illegal International Legal Reform, 111 Ethics 673 (2001), and Buchanan, Reforming the International Law of Humanitarian Intervention, in Humanitarian Intervention: Ethical, Legal and Political Dilemmas 130 (J. L. Hozgrefe & Robert O. Keohane eds., 2003). For the view that secondary rules of state responsibility do not provide a legal basis for AHI in cases in which the primary rules of international law do not permit resort to force for humanitarian purposes, see Federica Paddeu, Humanitarian Intervention and the Law of State Responsibility, 32 Eur. J. Int'l L. 649 (2021).

64. For discussion, see J. L. Holzgrefe, The Humanitarian Intervention Debate, in Humanitarian Intervention: Ethical, Legal and Political Dilemmas 15 (J. L. Hozgrefe & Robert O. Keohane eds., 2003); Neil A. Lewis, The Rationale: A Word Bolsters Case for Allied Intervention, N.Y. Times, Apr. 4, 1999; Christopher Greenwood, Yes, But Is the War Legal?, Observer, Mar. 28, 1999. See also Independent International Commission on Kosovo, Kosovo Report (2000), available at https://www.law.umich.edu/facultyhome/drwcasebook/Documents/Documents/The%20Kosovo%20Report%20and%20Update.pdf; Ruth Wedgwood, NATO's Campaign in Yugoslavia, 93 Am. J. Int'l L. 828 (1999); A. Cassese, Ex iniuria ius oritur: Are We Moving Towards International Legitimation of Forcible Humanitarian Countermeasures in the World Community?, 10 Eur. J. Int'l L. 23 (1999).

65. See Thomas M. Franck, Interpretation and Change in the Law of Humanitarian Intervention, in Humanitarian Intervention: Ethical, Legal and Political Dilemmas 204 (J. L. Hozgrefe & Robert O. Keohane eds., 2003). Others maintain that this did not amount to the positive authorization required by the Charter. See Simon Chesterman, Just War or Just Peace? Humanitarian Intervention and International Law (2001), at 213.

66. Ian Hurd, Is Humanitarian Intervention Legal? The Rule of Law in an Incoherent World, 25 Ethics & Int'l Affs. 293 (2011). It is widely acknowledged that indeterminacy regarding the international law on the resort to force is a central obstacle to legally differentiating between just and unjust combatants. See, e.g., McMahan, supra note 9; Dill, supra note 7; Seth Lazar, Complicity, Collectives, and Killing in War, 35 Law & Phil. 365 (2016).

67. Several scholars have proposed mechanisms for institutionalizing procedures for assessing and authorizing the preventive use of force. See Allen Buchanan & Robert O. Keohane, The Preventive Use of Force: A Cosmopolitan Institutional Proposal, 18 Ethics & Int'l Affs. 1 (2004); McMahan, supra note 30; Betz, supra note 30.

68. David Luban, Intervention and Civilization: Some Unhappy Lessons of the Kosovo War, in Global Justice and Transnational Politics 79, 84–85 (Pablo de Greiff & Ciaran Cronin eds., 2002).

69. Jane Stromseth, Rethinking Humanitarian Intervention: The Case for Incremental Change, in Humanitarian Intervention: Ethical, Legal, and Political Dilemmas 233 (J. L. Holzgrefe & Robert O. Keohane eds., 2003).

70. See Bellamy, supra note 2.

71. See Hurd, supra note 59.

72. For discussion, see Mohammed Ayoob, Humanitarian Intervention and State Sovereignty, 6 Int'l J. Hum. Rts. 81 (2002); Ian Hurd, Legitimacy, Power, and the Symbolic Life of the UN Security Council, 8 Global Governance 35 (2002). See also Buchanan, supra note 63, Reforming the International Law, at 162.

73. For example, Caney, supra note 9.

74. Though states have, for a long time, abused the “humanitarian” justification as a pretext for furthering their national interests abroad. See, e.g., Aidan Hehir, Humanitarian Intervention (2009); Chesterman, supra note 65. But the doctrine of the “responsibility to protect,” as noted earlier, was only adopted by the UN in 2005. For general discussion of the historical foundations of the laws of war, see Pablo Kalmanovitz, The Laws of War in International Thought (2020).

75. For discussions of how IHRL better tracks individualist commitments of revisionist theory, see Dill, supra note 31; Eliav Lieblich, The Facilitative Function of Jus in Bello, 30 Eur. J. Int'l L. 321 (2019); Haque, supra note 7; Luban, supra note 46; and Luban, Just War and Human Rights in his Military Ethics (2008).

76. For discussion, see Dill, supra note 31; Kenneth Watkin, Fighting at the Legal Boundaries: Controlling the Use of Force in Contemporary Conflict (2016), at 121–156; Lawrence Hill-Cawthorne, Humanitarian Law, Human Rights Law and the Bifurcation of Armed Conflict, 64 Int'l Compar. L. Q. 293 (2015); Oona A. Hathaway et al., Which Law Governs During Armed Conflict? The Relationship Between International Humanitarian Law and Human Rights Law, 96 Minn. L. Rev. 1883 (2012); Christian Tomuschat, Human Rights and International Humanitarian Law, 21 Eur. J. Int'l L. 15 (2010); Robert Kolb, The Relationship Between International Humanitarian Law and Human Rights Law: A Brief History of the 1948 Universal Declaration of Human Rights and the 1949 Geneva Conventions, 38 Int'l Rev. Red Cross 409 (1998).

77. But similar fundamental ideas became prominent during the Enlightenment and profoundly shaped the US Declaration of Independence in 1776 as well as the French Déclaration des droits de l'homme et du citoyen in 1789.

78. It does, however, govern the use of force in law enforcement. For example, it prohibits the arbitrary deprivation of life and is based on central assumptions about the morality of defensive harming, including considerations of necessity, proportionality, and just cause (for instance, International Covenant on Civil and Political Rights, Article 6(1)).

79. For lawyers, this is a matter of how we should interpret lex specialis. My concern here is with the moral case.

80. For the view that IHRL should prevail at least in some instances even in armed conflict, see Henry J. Steiner, Philip Alston & Ryan Goodman, International Human Rights in Context: Law, Politics, Morals (3d ed. 2008), at 395. For general discussion, see Human Rights (Louis Henkin et al. eds., 2d ed. 2009), at 413–415.

81. For the traditional view concerning the “law of nations,” see Banco Nacional de Cuba v. Sabbatino, 376 U.S. 398, 422 (1964).

82. Curtis A. Bradley & Jack A. Goldsmith, Customary International Law as Federal Common Law: A Critique of the Modern Position, 110 Harv. L. Rev. 815, 832 (1997) (quoting Restatement (Third) of the Foreign Relations Law of the United States §§ III cmt. d, 115 cmt. e (1987), pt. VII, Introductory Note, at 144–145).

83. A notion emphasized by Gareth Evans, cochair of the ICISS commission, on numerous occasions.

84. See Tadros, supra note 7, at ch. 12.

85. See Scheffer, supra note 29, at 426.

86. See Waldron, supra note 57.

87. One might also appeal to the notion of the “responsibility while protecting.” See Oliver Stuenkel, Responsibility While Protecting, in The Oxford Handbook of the Responsibility to Protect 620 (Alex J. Bellamy & Tim Dunne eds., 2016).

88. For example, after World War I, there was no way to try the Kaiser, because there was not yet a crime of aggression. It was only because the Kellogg Briand Pact of 1928 made the crime of aggression illegal that it was possible to try the Nazis for this crime after World War II. For discussion, see Oona A. Hathaway & Scott J. Shapiro, The Internationalists: How a Radical Plan to Outlaw War Remade the World (2017). In addition, the term “genocide” was only coined in 1943–1944, after Polish-American lawyer Raphael Lemkin recognized the need for a word to capture the human destruction of the Holocaust and resolved to make it an international crime. For an account of Lemkin's monumental efforts, see Samantha Power, A Problem from Hell: America and the Age of Genocide (2002), at 47–60.

89. For example, Kofi Annan, Speech to the General Assembly, U.N. Doc. SG/SM/7136GA/9569: Secretary-G, Sept. 20, 1999, 2.