In their recent blog post “Surveying Proportionality: Whither the Reasonable Military Commander?” Laurie Blank, Geoffrey S. Corn, and Eric Jensen level three criticisms against the study of collateral damage with surveys, in general, and against the survey I recently started circulating entitled “The Meaning of Proportionate Collateral Damage” in particular. First, they criticize that the scenarios presented in the survey lack context. Second, they find fault with the fact that the survey asks people to judge the consequences of attacks rather than to evaluate their anticipated results in accordance with international law. Third, and this is the main thrust of their criticism, they disapprove of the survey’s intended audience: I am interested in the judgments of lay people rather than only in the views of military experts. The three choices underlying these features of the survey are interconnected. Nonetheless, I will address the three criticisms in turn.


Blank, Corn, and Jensen are, of course, right that proportionality calculations in the real world will often take contextual factors into account which are omitted in the survey. Crucially, after all the contextual factors have been considered, there is still a judgment to be made about the importance of the military advantage in light of the harm the attack is likely to cause. Unless collapsed into necessity, a proportionality judgment inevitably involves the weighing of human life and military gain. If a survey featured scenarios that elaborated on factors like “the broader enemy situation,” “the exigencies of the tactical situation,” or “the weaponeering process,” then the responses would be indicative at least partly of people’s interpretations of these factors, distorting what I am endeavoring to gauge: their views on arguably the hardest part of the proportionality judgment which is the decision of how much loss of life is commensurate to a military end. Moreover, while the contextual factors taken into account in a targeting decision obviously differ depending on the belligerent, the theatre, and the kind of targeting, I contest their implicit assumption that proportionality calculations are never based on just the kind of information provided in the scenarios. I want to stress though that the construction of the scenarios, namely the choice to strip the core question of context, is a methodological one, not an expression of the certainly equally false assumption that most proportionality judgments are made in this way most of the time.


Blank, Corn, and Jensen also correctly observe that civilians, both uninvolved civilians as well as those who live with armed conflict, base their judgments of warfare on its results, not least because that is often all they have to work with and that is what affects them the most. There are obviously two options, either, to ask respondents to put themselves into the shoes of a military decision-maker or to ask them to assume the role they actually have in war: that of an outside spectator or that of being at the receiving end of military decision-making. In the end, I chose the latter, partly because of the significant challenges for the lay person to fully understand the more technical parameters that feed into decision-making in war, such as weaponeering and mitigation, parameters that I exclude from the scenarios also for the reason mentioned above. This choice would be problematic if I asked people to make judgments about military decision-makers. But, I am asking respondents to judge the results of an attack not the reasonableness of a decision or the merit or moral status of a decision-maker. We all understand that a lot can happen between the intention of a decision-maker and the results of her actions. The impetus of the research is to shed light on the workings and effects of the proportionality principle. This is a continuation of my book, Legitimate Targets? which explores the complicated dynamics between strategic, moral, and legal considerations in the space afforded by the indeterminacy of the laws of war.

Systematizing the views people develop from the perspective they in fact have on war will be useful, I hope, for military commanders, not as the one and only touchstone of proportionality, but as an important data point to inform their decisions. Victory beyond the battlefield, in the sense of achieving a political or morally relevant goal, in the 21st century depends in part on various audiences’ perceptions of legitimacy. As one former commander put it: “it is all about winning the narrative.” Understanding what makes an individual consider the death of another a legitimate means to a military end, and having solid knowledge of what we might somewhat cynically call people’s “collateral damage tolerance,” in that sense is a military and strategic imperative. It may be a socially desirable project to help people empathize with military decision-makers by asking them to put themselves into their shoes and make prospective proportionality judgments. Empathy in war is highly desirable. But the primary aim of this project is to understand reality, namely the meaning people attribute to collateral damage already inflicted, not to change it.


This brings me to the merits and dangers (as the Blank, Corn, and Jensen perceive them) of asking people without military expertise about their views on combat operations. Let me start by emphasizing that my research absolutely takes into account the views of military experts. The survey, which by no means excludes serving members of armed forces or people with a military background, asking specifically about people’s prior expertise and experience, is only one dimension in a multi-pronged research project, which also involves in-depth interviews with military practitioners. One aim of the project is to systematize what military commanders consider proportionate collateral damage and if there is a convergence of views within this group, whether and how they differ from the perceptions of various lay audiences. Elucidating the notion of the reasonable military commander is a primary concern of this research.

As far as the role of lay people in normative assessments of warfare is concerned, I respectfully disagree with the authors’ denial that “you, or I, or anyone can accurately and meaningfully assess the proportionality of an attack after the fact and without full knowledge of the circumstances at the time of the attack.” I am not committed to the view that there is such a thing as an “accurate proportionality judgment,” but why should civilians’ judgments of the proportionality of an attack’s results be meaningless? While lack of military expertise might cast doubt over the sensibility of asking lay respondents about their interpretations of some of the contextual variables Blank and her colleagues list — such as a weaponeering process, the core judgment which the scenarios evoke, of how to weigh human life, and military gain — is not a technical military one, as military practitioners themselves often stress. It is a judgment informed by our most basic moral commitments regarding inter alia the validity and parameters of lesser evil justifications. In some militaries, in certain contexts this is in fact a decision made by civilian political leaders, not by military commanders.

I more strongly disagree with the tenor of the critique that asking lay audiences about their views on warfare is positively dangerous. Blank and her colleagues say it “risk[s] producing an even greater attenuation between scholarly discourse and public perception on one side, and the realities of military operations and operational law on the other.” I agree that this attenuation is worrisome. It is probably a burden to conscientious military commanders and a strategic problem for state belligerents concerned with their public image. In addition, if public perceptions of proportionality systematically differ from the operationalization of proportionality in reality, as Blank, Corn and Jensen suggest, then law must be perceived by civilians as failing in its task to protect them. But how is ignoring the views of lay people a solution to any of those problems? Shouldn’t we want to have systematic knowledge about the reasons for this attenuation? Should we not seek to understand which variables most immediately determine how an individual positions herself in this disagreement? I doubt that the only fault line in perceptions of collateral damage is between respondents with and without military expertise, but the survey specifically asks people to explain their professional background. Rather than obscuring the likely role of the latter in influencing people’s understandings of proportionality thus potentially exacerbating existing disagreement, the survey can enhance our understanding of each other’s positions by highlighting the variables that contribute to differences in what we perceive to be proportionate collateral damage.

As I said, this survey does not evaluate military decision-makers’ choices. But the authors’ critique raises a larger question about what the implications are of their declaring the views of lay people on those choices simply meaningless. Would the notion that how we wage war can only be assessed by those who do wage war not amount to an abdication of moral responsibility of civilians for actions that are undertaken in their name and in democratic societies with their indirect consent? Do we want to burden military commanders, who are subjected to the unique stressors of warfare, with the sole responsibility of figuring out what is appropriate conduct in war? Allow me to bring the problem with what Blank, Corn, and Jensen are asking — only military experts should evaluate the rules and the conduct of war — into sharper relief by drawing attention to the fact that societies fairly regularly have to grapple with morally difficult questions the answer to which could never be adequately determined without drawing on specialist expertise. Yet, we do not therefore think that we can dispense with a broader societal consensus on the underlying moral issues. Neither do we tend to treat the views of lay people who are affected by how we legally regulate these issues as irrelevant or even dangerous to consider.