(Update, Friday, July 28, 2006: Welcome Instapundit readers - the first link from Instapundit that was bad (my fault) is here, on proportionality and jus ad bellum. And here is a post on the meta theory of the just war, comparing Walzer and Catholic versions of just war theory.)
(Update, Friday, July 21, 2006: Welcome to readers from Opinio Juris, Hugh Hewitt, Steve Bainbridge, and a couple of other places that seem to have picked up this post. I've revised slightly the opening paragraph and made some stylistic changes in the rest of the introduction to make it an easier read; nothing changed in the body of the discussion. Readers may also be interested in my later post on the obligations of defenders under the laws of war not to commingle civilian and military objects, here, as well as my 2003 New York Times Magazine essay Who Owns the Rules of War, at SSRN, here or at the Crimes of War Project archive, here. My SSRN author page, with a selection of academic pieces on laws of war and just war theory, is here.)
(Update, Monday, July 24, 2006. Please take the time to read Professor Geoff Corn's thoughtful and important comment below in the comments section; I am reposting it as well as a new post on the blog. Professor Corn comes to law school teaching from a highly distinguished background as the Army JAG's chief law of war person - not to mention his extremely interesting posts as a guest blogger a few months back at Opinio Juris. His observation that "excessive," as distinguished from "disproportionate," is the actual language of Protocol I is a very important addition to the debate. (Corrected from earlier - I was brain dead, sorry!) I also want to thank Georgetown law professor Anthony Arend, who also heads the school's international law and politics institute, for his kind words about the proportionality discussion - his blog provides further analysis and links, here.)
(Update, Monday, July 24, 2006. Please also see the very interesting discussion of proportionality over at Opinio Juris, here by Kevin Heller and here by Roger Alford.)
A great deal of discussion is underway concerning proportionality in the Lebanon war, much of it, in my view, underinformed. Many writers seem unaware of the difference, for example, between proportionality as a concept in jus in bello and proportionality as a concept in jus ad bellum. Many more seem to think that jus in bello proportionality is a matter of making sure that civilian casualties are approximately equal on both sides. Others seem to think the jus in bellum proportionality means that war aims must be limited to restoring the status quo ante.
We now also have the UN High Commissioner for Human Rights, Louise Arbour, weighing in with threats of criminal liability for breaches of jus in bello proportionality.
I am in the middle of revising some things, and do not have time to address the issue specifically. I am, however, excerpting below passages from an expert declaration on laws of war issues I prepared in the last Agent Orange litigation that addresses basic issues on jus in bello proportionality, the difficulties of criminal liability for alleged breaches of proportionality duties, and what the Yugoslavia tribunal prosecutor's office said - under Louise Arbour herself, if I recall correctly, although she joined the Supreme Court of Canada in 1999, so perhaps not - when it was raised as an issue of potential NATO liability in the Kosovo bombing campaign.
What the Yugoslavia prosecutor's office thought of NATO - read US - liability in Kosovo is, in one sense, neither here nor there, as the US would not recognize that court's jurisdiction over it or its military, nor does it see the Yugoslavia tribunal's jurisprudence as anything authoritative or binding. But it is striking to read just how limited the Yugoslavia prosecutor's own office found the concept of proportionality back when it was potentially NATO in the dock.
(I should add one note with reference to the discussion below. One can find in the Yugoslavia court cases many instances of criminal liability for wanton and disproportionate devastation, involving, say, a Serb paramilitary unit deliberately trashing a village. Those cases arise under a concept of wantonness and depravity of destruction - wanton and depraved going to the issue of mental intent. That is not the issue of proportionality as such - proportionality as such is the situation where a commander, without any special or extra intent of wanton and depraved destruction, was nonetheless found liable under the laws of war for destruction because the court simply found it disproportionate as such.)
The full declaration from which this is drawn can be found on SSRN, here, and the reply declaration to the plaintiffs experts (Michael Reisman and I were experts for the defendant corporations, and independently reached essentially the the same conclusions on all these matters) can be found on SSRN, here.
If you are interested in at least partly contrary scholarly views, you might consult Notre Dame professor Mary Ellen O'Connell, here, UCLA professor Steven Bainbridge, here (actually on just war theory, but follow the various replies and counter-replies for some discussion of the positive law, including from Georgetown professor Anthony Arend at Professor Bainbridge's blog), and if you have Westlaw, you can get to the affidavit for the Agent Orange plaintiffs by University of Houston Law Center professor Jordan Paust (no link). For a defense of the jus in bello legality of Israel's actions, see this article by Gidon D. Remba, here; the article addresses not only the proportionality argument, but also the context of forces that deliberately site themselves among civilians and civilian objects.
(I re-numbered the paragraphs below to start with 1 ... also, the endnotes matter a great deal in this discussion.)
1. The rule of proportionality and problems in its application. The fundamental customary law rule at issue in each of these scenarios is proportionality. This is how properly to weigh the requirements of military necessity – what might be called the “importance of winning” – against collateral damage, particularly to civilians and civilian objects. This rule of proportionality is so ancient and deeply embedded in the laws of war that the Hague Regulations do not see the need to state the general proportionality rule as such. The US Army’s Law of Land Warfare, which generally follows the Hague Regulations, sets out the general rule that “loss of life and damage to property must not be out of proportion to the military advantage to be gained.” This was the standard in force for US forces in the Vietnam War and is still the US military standard today.
2. Although there is general agreement about the existence of the rule of proportionality, there is no similar agreement about how the concept should be applied. The 1999 Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign Against the Federal Republic of Yugoslavia, which considered allegations that NATO forces breached the proportionality rule in the Kosovo war, summarized the difficulties even under the law today:
“The main problem with the principle of proportionality is not whether or not it exists but what it means and how it is to be applied. It is relatively simple to state that there must be an acceptable relation between the legitimate destructive effect and undesirable collateral effects. … It is much easier to formulate the principle of proportionality in general terms than it is to apply it to a particular set of circumstances because the comparison is often between unlike quantities and values. One cannot easily assess the value of innocent human lives as opposed to capturing a particular military objective.”
The proportionality calculation is therefore inherently open-ended, imprecise and subjective. Moreover, it is a calculation that must take place constantly up and down the chain of command, in strategic matters as well as tactical matters, in the general’s headquarters as well as in the mind of the junior officer on the move in the field.
3. By reason of this inherent subjectivity and imprecision, people with different backgrounds and in different circumstances can easily reach different but equally legitimate conclusions on exactly the same facts. As the Final Report notes, for example, it is “unlikely that a human rights lawyer and an experienced combat commander would assign the same relative values to military advantage and to injury to noncombatants. Further, it is unlikely that military commanders with different doctrinal backgrounds and differing degrees of combat experience or national military histories would always agree in close cases.” Even from the standpoint of a reasonable military commander, commanders with the same training are likely to come to varying conclusions on the same facts. For this reason, the law of war has traditionally vested very great discretionary powers with commanders to make these determinations. A Department of Defense General Counsel letter correctly says that it is “universally recognized that the laws of war leave much to the discretion of the military commander.” Such discretion is a constant of the laws of war.
4. Proportionality and criminal liability. Because the calculation of proportionality lies in the hands of military commanders, the question of proportionality is generally satisfied by those commanders making a genuine attempt to determine both sides of this proportionality calculation and to weigh them against each other. Once a good faith attempt has been made to weigh these risks and benefits, it is recognized that this judgment of proportionality should be respected, absent some showing of truly extraordinary disregard for undertaking proportionality calculations at all – that is, disregard so egregious that it would have been palpable and obvious to anyone that it crosses the line into intentional depravity.
5. The reason for this deference to the commander’s discretion is that the body of law at issue is, with respect to individual liability, entirely criminal. The standards, therefore, of intent and culpability are those of the criminal law. But unlike ordinary criminal law, these standards are applied in circumstances of war and peace where the stakes are enormous, involving both immense forces of destruction and enormous political consequences. States have been profoundly unwilling to turn otherwise honorable soldiers into mass murderers by the second guessing of a court after the fact; state practice has required, instead, obvious intentional depravity, an utter indifference even to making a calculation of proportionality.
6. How seriously international law takes the discretion of commanders and, therefore, how egregious such conduct would have to be in order to fall outside the scope of that discretion, is illustrated tangentially in the Nuremberg Hostage Case decision. As part of a larger case concerning reprisals against hostages, the German commander was also accused of scorched earth tactics so destructive as to amount to disproportionate devastation not justified by military necessity. Because the court found no element of depravity in the destruction – no evidence of utterly egregious indifference to the calculation of proportionality – the court found no war crime on the basis of a lack of proportionality:
“There is evidence in the record that there was no military necessity for this destruction and devastation. An examination of the facts in retrospect can well sustain this conclusion. But we are obliged to judge the situation as it appeared to the defendant at the time. If the facts were such as would justify the action by the exercise of judgment, after giving consideration to all the factors and existing possibilities, even though the conclusion reached may have been faulty, it cannot be said to be criminal …
We are not called upon to determine whether urgent military necessity for the devastation and destruction in the province of Finmark actually existed. We are concerned with the question whether the defendant at the time of its occurrence acted within the limits of honest judgment on the basis of the conditions prevailing at the time . . . the defendant may have erred in the exercise of his judgment but he was guilty of no criminal act.” (emphasis added)
7. The lesson of The Hostage Case, therefore, is that the court respected the judgment of the commander even in a case involving extreme scorched earth tactics, which involved devastation of an area approximately the size of Denmark and which left, according to the indictment, some 61,000 civilians starving and without shelter at the onset of winter in Scandinavia. It was unwilling to substitute its own judgment so long as it appeared that an “honest” attempt, a good faith attempt, was undertaken in making that judgment. The court was not concerned to determine whether conditions of urgent military necessity “actually existed,” but only whether the commander concluded in good faith that they did. That condition satisfied, the court refused to substitute its own judgment.
8. The notion that proportionality decisions are generally protected as an exercise of discretion means, as noted above, that as a matter of international and military law, the issue of proportionality has been largely regarded as non-reviewable by courts, because it is not considered suitable for second-guessing by courts, international, military or otherwise. As Francoise Hampson, who is a member of the ICRC’s expert committee on customary international law, concludes:
“State practice recognizes that judgments about military necessity often require subjective evaluations with incomplete information on the battlefield and imperfect knowledge of where the failure to take action might lead. For this reason, great discretion has always been attached to commanders' judgments, especially those made under battlefield conditions. Rarely, if ever, is the judgment of a field commander in battle -- balancing military necessity and advantage -- subject to legal challenge, let alone criminal sanction.”
Thus, while proportionality indeed exists as a matter of international law, it is generally not reviewable by courts, except in cases so egregious that they go far beyond what the Amended Complaint alleges, to circumstances constituting intentional depravity. Not even the horrific scorched earth tactics of The Hostage Case qualify, given the commander’s good faith judgment.
9. Applying this standard to the circumstances alleged in the Amended Complaint, and as reiterated in Operation Ranch Hand [the Vietnam War Agent Orange program under litigation], the extensive consultations and discussions by commanders of military benefits and expected civilian costs easily met, in my view, the international legal requirements for respecting commanders’ discretion. These discussions took place from the President down to local commanders. They involved extensive legal, diplomatic, and military review of both the military benefits and the possible consequences to noncombatants. The requirements of international law would have been met, in my view, with far less discussion; much of the discussion that took place was motivated by reasons of political prudence, rather than legal necessity, and the extent and depth of discussion went well beyond the calculations of proportionality that the law required.
10. State practice and the paucity of judicial authority on proportionality. The non-reviewability of proportionality calculations as a matter of international and military law means, as a consequence, that there is a paucity of judicial authority on the subject. This is not surprising. State practice, as noted in part II, can take the form of state action and state inaction. Thus, a lack of prosecutions for disproportionality itself provides evidence of customary international law on the subject. I have followed this body of law for many years, discussing it repeatedly with military lawyers, human rights lawyers, and scholars, and I am not aware of any court martial or other legal case since the Second World War that directly turns on disproportionate devastation by a commander – meaning a case where the legal issue is disproportionality as a war crime as such. This is despite the fact that proportionality figures at the very center of every commander’s legal responsibility under the law of war. Unsurprisingly, therefore, a leading scholar on proportionality has concluded:
“National and international judicial or arbitral decisions which might clarify the rule of proportionality and assist in determining its meaning within the context of  Protocol I are relatively sparse, particularly if cases involving reprisals [such as the Hostages case] are disregarded. The rules of international law relating to combat have rarely been made the basis of war crime trial proceedings. For example, other than trials arising out of reprisal incidents, no such trials directly relevant to the proportionality issue are reported in the most comprehensive set of war crimes reports, the fifteen volume Law Reports of Trials of War Criminals published for the United Nations War Crimes Commission following the Second World War.”
11. The closest that I am able to come to a post-Second World War judicial view on the matter is the aforementioned analysis offered by the Final Report, asked to respond to claims of disproportionate attack in the 1999 Kosovo war by NATO forces. The Final Report, however, not only refused to find actions that could be prosecuted, it refused even to recommend any action for investigation by the Prosecutor. In addition, the very fact that the ICTY prosecutor had even investigated the proportionality of the bombings elicited fierce criticism by various NATO states, outraged that questions of proportionality should have been subject to even this level of review. As noted in part II, state practice can take the form of state action and state inaction. Thus, these strong reactions are legally relevant because they reflect a deeply held view by states that proportionality calculations lie within a commander’s discretion and are generally not reviewable except in absolutely egregious cases.
12. The foregoing is not to suggest, however, that because determinations of proportionality are generally not reviewable by courts after the fact means that there is nothing in place by which to inform and temper judgments of proportionality. Rather, state practice and international law have concluded that the best means of ensuring that the proper balance is struck between the requirements of military necessity and collateral damage is by the actions and training of military commanders taken before the fact. It is understood, in my experience, that as a matter of both policy and state practice, proportionality is not a matter that can be effectively policed post hoc by courts; it is inherently too much a matter of discretion. What matters, instead, is a deep emphasis on the training and professional formation of military officers in order to make proportionality calculations a serious and integral part of military action. Proportionality judgments should be incorporated as an inescapable step in drawing up the rules of engagement in advance of military action. These judgments of proportionality can be incorporated into the planning of forms of attack and defense, into preparations for what weapons will be taken to the battlefield, into logistical requirements, into the placement and movement of troops, and the proportionate circumstances of their use planned as with every other facet of war-planning; those judgments of proportionality that must unfold as battle unfolds will be undertaken because they are already incorporated under the rules of engagement into commanders’ on-going responsibility. As the distinguished military historian Sir John Keegan has written,“‘the experience of land war in two world wars must raise a question as to whether formal legal codification is necessarily superior to notions of custom, honour, professional standards, and natural law’ in making for battlefield decencies. … There is no substitute for honour as a medium of enforcing decency on the battlefield, never has been and never will be.”
13. Thus, as the paucity of cases addressing proportionality confirms, states believe that judgments of proportionality properly lie within a commander’s discretion and cannot be effectively policed ex post facto by courts. It would be novel, at the very least, for a court to enter an area that neither civilian nor military courts across many nations, over a long period of time, have thought appropriate to go, to make new international law in what is regarded as the essence of discretion.
 The phrase is Michael Walzer’s and it captures an important, yet sometimes overlooked, fact about the moral structure undergirding the laws of war. Winning, Walzer says, is important, despite the fact that the law imposes rules on how winning may be achieved, and if you do not believe that it is important that your side win in war, then morally you cannot justify the violence and destruction entailed by fighting. See Michael Walzer, Just and Unjust Wars: A Moral Argument With Historical Illustrations 109-110 (1977).
 US Field Manual supra note 10, at 19, para. 41.
 1977 Protocol I sets out a somewhat more elaborate standard which focuses directly on noncombatants; it prohibits attacks 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.” 1977 Protocol I, Art. 51(5)(b). This definition, in my view, has certain advantages of clarity and specificity in laying out a standard for acceptable collateral damage, at least with respect to civilians, and it has been widely accepted in the world. Although it informs my thinking, I have not used it directly here for two reasons. First, the United States has not ratified 1977 Protocol I, and therefore it is not bound by its formulations as a matter of treaty law. It has also objected to some articles as departing from existing customary international law. See Michael J. Matheson, The United States Position on the Relation of Customary International Law to the 1977 Protocols Additional to the 1949 Geneva Convention, 2 Am. U. J. Int'l L. & Pol'y 419, 424-27 (1987); see also Meron, supra note 16, 62-70. Second, the United States, among other countries, has also raised objections (in my view, correctly) to the wording, or at least to some interpretations, of this particular provision, viz., the phrase “concrete and direct.” The US objects to those terms being understood to mean advantages in the “tactical” situation prevailing at that moment only; the view of the United States seems to be that tactical situations can only be evaluated in relation to a larger strategic view. For a summation of states’ concerns on this matter in the drafting of 1977 Protocol I, see ICRC Commentary, supra note 77, Art. 57, at p. 685, paras. 2217-18.
 Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign Against the Federal Republic of Yugoslavia, 1999, § 48, available at
 Id., § 50.
 First Letter from J.Fred Buzhardt, General Counsel of U.S. Department of Defense, to Senate Foreign Relations Committee Chairman J.W. Fulbright, 1971, reprinted in “United States: Department of Defense Position With Regard to Destruction of Crops Through Chemical Agents,” 10 I.L.M. 1300, 1303 (1971).
 United States of America v. Wilhelm List, et. al., “The Hostage Case”, Case No. 7, 11 Law Reports of Trials of War Criminals, 1296-1297 (1949)
 “Scorched earth” here risks understating the enormity of the devastation. The German army in Finland in 1944, faced with a separate peace between Finland and the Soviet Union, retreated to deeper defensive positions in Norway. Believing itself to be pursued by a much larger Soviet army, as part of its retreat, it ordered a complete evacuation and total destruction of an area in Norway approximately the size of Denmark. See Howard S. Levie, Terrorism in War: The Law of War Crimes 339-40 (1993). The devastation was described in the US indictment at Nuremberg of the German commanders:
“[D]efendant Rendulic … issued an order, to troops under his command and jurisdiction, for the complete destruction of all shelter and means of existence in, and the total evacuation of the entire civilian population of, the northern Norwegian province of Finnmark. During the months of October and November 1944, this order was effectively and ruthlessly carried out … evacuated residents were made to witness the burning of their homes and possessions and the destruction of churches, public buildings, food supplies, barns, livestock, bridges, transport facilities, and natural resources of an area in which they and their families had lived for generations. Relatives and friends were separated, many of the evacuees became ill from cold and disease, hundreds died from exposure or perished at sea in the small boats and fishing smacks used in the evacuation, while still others were summarily shot for refusing to leave their homeland; in all, the thoroughness and brutality of this evacuation left some 61,000 men, women, and children homeless, starving, and destitute.” (Count 2, para. 9(a), Indictment in The Hostage Case, (United States of America v. Wilhelm List et. al.),supra note 88, 11 Law Reports of Trials of War Criminals 770(1948).)
Thus, despite the extreme devastation created by the German commanders, the Nuremberg court nonetheless – and indeed in summary fashion – acquitted the German commanders on this charge.
 Francoise Hampson, Military Necessity, in Crimes of War, 251 (Roy Gutman and David Rieff gen. eds., Kenneth Anderson, legal ed., 1999). This conclusion is also supported by state practice, for example, the Austrian Military manual states that: “A direct military advantage is … anticipated if the commander has an honest and reasonable expectation that the attack will make a relevant and proportionate contribution to the attainment of the purposes of the overall operations. Deference must be paid to the judgments of responsible commanders, based on information available to them at the time, and taking into account the urgent and difficult circumstances under which such judgments must be made”; and the Canadian military manual states that: “A concrete and direct military advantage exists if the commander has an honest and reasonable expectation that the attack will make a relevant contribution to the success of the overall operation.” (emphasis added) See Knut Dörmann, Elements of War Crimes under the Rome Statute of the International Criminal Court: Sources and Commentary, 165, 172-73 (2003) (citing both manuals and concluding that: “There is probably no doubt that a court will respect judgments that are made reasonably and in good faith on the basis of the requirements of international humanitarian law”).
 See e.g., Thirlway, supra note 16
 Even arguably the closest to a true proportionality case, The Hostage Case in fact was not centrally about proportionality of devastation; it was instead about the Second World War legal standard for reprisals against third party, innocent hostages for the activities of others engaged in resistance against the occupier; the proportionality of such reprisals was an important element of law under Second World War legal standards (all such reprisals against hostages are today prohibited by the 1949 Geneva Conventions). The allegation of disproportionate devastation – devastation of civilian property – was introduced tangentially and dismissed pretty much summarily. It is clear that a charge based on proportionality alone would not have been successful. See supra note 88, 89.
 Lieutenant Colonel William J. Fenrick, The Rule of Proportionality and Protocol I in Conventional Warfare, 98 Mil. L. Rev. 91, 112 (1982).
 The sharp reaction of the US and other states to the ICTY prosecutor’s action is an example of state reactions that are a form of state practice; thus, it is of legal, and not merely political, interest that the United States and others objected so strongly even to the formation of a committee to offer a report to the ICTY prosecutor. See, e.g., Jonathan D. Tepperman, Commentary; Embrace the Tribunal: Prosecuting War Criminals Is In Everyone’s Interests, Los Angeles Times, Jan. 18, 2000, at B-7 (op-ed) (ICTY Prosecutor del Ponte “announced that she was investigating complaints . . . into the conduct of NATO’s pilots . . . . No sooner had Del Ponte spoken than American officials fired back. The White House complained that ‘NATO undertook extraordinary efforts to minimize collateral damage’ and . . . ‘any inquiry into the conduct of its pilots would be completely unjustified’”); Rowan Scarborough, U.S. denounces U.N. probe of NATO bombings; Says inquiry is ‘unjustified’, Washington Times, Dec. 30, 1999, at A1 (“Former military officers also expressed shock that such an international investigation could result in indictments, saying bombing blunders against civilians at 20,000 feet are not a criminal matter.”) Not receiving cooperation from NATO, the Final Report relied on nongovernmental human rights monitors, submissions from the governments of the Federal Republic of Yugoslavia and the Russian Federation, academic submissions, and press reports for its factual claims. See Final Report, supra note 85 at part III, list of materials utilized.
 The International Committee of the Red Cross, in its training missions to militaries around the world to inculcate the laws of war, offers an example of what ante hoc training looks like. The ICRC Handbook on the Law of War for Armed Forces, for example, gives training lessons on the rule of proportionality. The Handbook restates the rule as saying that an “action is proportionate when it does not cause incidental civilian casualties and damage which is excessive in relation to the value of the expected result of the whole military operation.” The Handbook then seeks to operationalize this abstract principle by training military commanders in ways to incorporate it practically into military rules of engagement. So, for example, “guidance to subordinates,” it says with reference to weighing up the costs and benefits of military operations, “shall be given in rules of engagement.” Frederic de Mulinen, Handbook on the Law of War for Armed Forces 93 (ICRC 1987).
 John Keegan, If you won’t, we won’t, The Times Literary Supplement, Nov. 24, 1995(quoting Sir Adam Roberts).
Friday, July 21, 2006
(Update, Friday, July 28, 2006: Welcome Instapundit readers - the first link from Instapundit that was bad (my fault) is here, on proportionality and jus ad bellum. And here is a post on the meta theory of the just war, comparing Walzer and Catholic versions of just war theory.)