On Saturday, I had the honor of speaking to the Médecins Sans Frontières (MSF) USA General Assembly. In preparing for my talk last week, I came across a section of the US Defense Department Law of War Manual — section — that I initially found puzzling. (Full disclosure: I worked as Special Counsel to the General Counsel at the Department of Defense Office of General Counsel when the Manual was issued, but played no role in its preparation. It should go without saying that the views expressed here are my own and not those of the US Department of Defense.)

Now that I have had more time to dig into the section, I have concluded that it is not well supported and, indeed, it may put the lives of medical and religious personnel — like those of the MSF doctors I spoke to — unnecessarily at risk. Indeed, taken to its logical conclusion, it threatens to eradicate proportionality as a condition of lawful military targeting altogether.


Section 7.8.2 first provides that medical and religious personnel “must not knowingly be attacked, fired upon, or unnecessarily prevented from discharging their proper functions.” So far so good. But then the first subsection,, provides:

Incidental Harm Not Prohibited. The incidental killing or wounding of such [medical and religious] personnel, due to their presence among or in proximity to combatant elements actually engaged by fire directed at the latter, gives no just cause for complaint. Because medical and religious personnel are deemed to have accepted the risk of death or further injury due to proximity to military operations, they need not be considered as incidental harm in assessing proportionality in conducting attacks.

On first read, this struck me as odd. How could it be that civilian medical personnel, who are specifically protected from being targeted, do not count as part of the proportionality analysis? So I looked to the citations.

The first is a 1959 book: Greenspan’s Modern Law of Land Warfare. The Manual cites Greenspan with the following parenthetical: “Medical personnel and chaplains ‘must accept the risks of accidental death or injury as a result of war operations.’” But that source only supports the proposition that medical personnel and chaplains accept the risk of death or injury, not that their deaths do not count in a proportionality analysis. (More in a moment on whether the two are one and the same.)

The next two citations are to other sections of the Manual: (“Harm to Certain Individuals Who May Be Employed In or On Military Objectives”) and (“Acceptance of the Risk From Proximity to Combat Operations”). So let’s consider each in turn.

First, section provides:

Harm to Certain Individuals Who May Be Employed In or On Military Objectives. Harm to certain persons who may be employed in or on military objectives would be understood not to prohibit attacks under the proportionality rule. These categories include:

  • persons authorized to accompany the armed forces;
  • parlementaires; and
  • civilians workers who place themselves in or on a military objective, knowing that it is susceptible to attack, such as workers in munitions factories.

These persons are deemed to have assumed the risk of incidental harm from military operations. Moreover, the law of war accepts that the defender may employ these persons to support military operations near or within military objectives. If these persons could have the effect of prohibiting attacks by the attacking force, then the defending force that used such persons in proximity to its forces or military objectives would be unlawfully using the presence of such persons to shield its operations or its military objectives from attack.

There are three sources cited for the sentence on civilian workers:

  1. The 2007 Commander’s Handbook on the Law of Naval Operations, para. 8.3.2 (“The presence of civilian workers, such as technical representatives aboard a warship or employees in a munitions factory, in or on a military objective, does not alter the status of the military objective. These civilians may be excluded from the proportionality analysis.”);
  2. Bothe, Partsch & Solf’s, New Rules, p. 303, which examines Additional Protocol I, article 51, para. (cited for the proposition that “[d]uring international armed conflict, workers in defense plants or those engaged in distribution or storage of military supplies in rear areas ‘assume the risk of incidental injury as a result of attacks against their places of work or transport.’”); and
  3. International Committee of the Red Cross, Draft Rules for the Limitation of the Dangers Incurred by the Civilian Population in Time of War, art. 6(3), 9 (Sept. 1956) (“Nevertheless, should members of the civilian population, Article 11 notwithstanding, be within or in close proximity to a military objective they must accept the risks resulting from an attack directed against that objective.”).

As was true of the Greenspan source discussed above, the second and third sources only support the idea that the civilians who are in close proximity to a military objective must accept the risks resulting from an attack directed against that military objective, not that such civilians do not count in the proportionality analysis.

Only the first — the 2007 Commander’s Handbook on the Law of Naval Operations — specifically states that civilians who “accept the risk” of presence near a military object do not count in the proportionality analysis. Given that this citation is relied upon in the Manual for a significant legal point, one might think it offers some justification for that position. But it does not: The only directly relevant sentences in the handbook are the two quoted in the Manual (above). Moreover, the handbook does not have a single citation to any source of law. (The much more reasonable reading is the traditional one: The presence of civilians in or on lawful military targets does not rule out the target, but the civilians do count in a proportionality analysis.)

The paragraph in on assumption of risk is supported only by a citation to the section of the Manual on human shields, 5.16, a section that has itself proven controversial (also discussed at this event by Marty Lederman at 1:08). The only mention of proportionality in the human shields section is in 5.16.1, which ends with a statement that

[T]his rule [on protected persons and objects, including “fixed medical establishments and medical units”] does not prohibit persons who would otherwise be civilians from participating in hostilities or assuming the risks inherent in supporting military operations. Incidental harm to those individuals would be understood not to prohibit attacks under the proportionality rule, and thus would not implicate this rule. [Emphasis added.]

There is one footnote to one source: Our old friend

Second, let’s consider Section It provides:

Acceptance of the Risk From Proximity to Combat Operations. During and after an engagement, such vessels [merchant vessels transformed into hospital ships] will act at their own risk. A hospital ship or coastal rescue craft operating in proximity to combat operations assumes a certain risk of damage as a result of lawful enemy operations, including misidentification by enemy or friendly forces.

This section is narrowly focused on a particular topic — hospital ships. It speaks, moreover, only to damage to the ships themselves, not to the people on board. In addition, the section says nothing about proportionality.

So let’s sum up: We have exactly one source in the Manual for the extraordinary proposition that medical and religious personnel need not be considered for purposes of proportionality analysis. That source was, like the Manual, authored by the US military, and it discusses the topic for two sentences without any citation.


But, you might say, several sources state that civilians “assume the risk” associated with proximity to a military objective. Perhaps “assuming the risk” means that such civilians no longer count for proportionality purposes. But if that is true, then the argument really does threaten to destroy proportionality altogether. That is because the sources that the Manual relies on for the idea of civilian “assumption of risk” apply not just to civilian medical and religious personnel but to all civilians in or near a military objective.

Consider Bothe, Partsch & Solf’s New Rules (source #2 for above). In the original source, the sentence quoted by the Manual has a footnote in which it makes clear that the assumption of risk applies to “civilians within military objectives or in their vicinity” (p. 344, n. 15 (emphasis added)). The third cited source, from the ICRC, similarly states that civilians “within or in close proximity to a military objective” accept the risks resulting from attack on that objective. Hence, these sources indicate that not only civilians who work in the facility that is a military object, but also those “in the vicinity of” or “in close proximity to” such an object “assume the risk” associated with their proximity to a legitimate military target.

Notice that the argument is no longer limited to medical and religious personnel. Those sources’ statements apply to all civilians within or in the vicinity or in close proximity to a legitimate military target. That may be true even if they did not know that they were in the vicinity of a military object (while refers to civilian workers who place themselves in or on a military objective “knowing” that it is susceptible to attack, none of the sources cited reference a knowledge requirement, nor does or So if the “assumption of risk” is sufficient to disqualify a civilian from consideration in a proportionality analysis, then any civilian in the vicinity of a military object no longer counts for purposes of a proportionality analysis. Which another way of saying proportionality is meaningless. After all, as long as the state is targeting a legitimate military object, any civilian men, women, and children “in the vicinity” have “assumed the risk” and so do not factor into the proportionality analysis.


But things get worse still: The US government has recently adopted an aggressive position that war-sustaining objects in a non-international armed conflict — like Syria, Yemen, Afghanistan, Iraq, etc. — are legitimate military targets. According to my successor at the Defense Department, Ryan Goodman, that includes the “economic infrastructure used to generate revenue for an enemy’s armed forces.” The weight of scholarly opinion has long maintained that such objects are not legitimate military targets. Since 2015, however, the French, Russians, and UK have joined the US in operations against ISIL oil revenues. (See Beth Van Schaack, Aurel Sari, and Marty Lederman on targeting ISIL oil transport trucks and cash stockpiles. Marty also notes Ryan’s subtle disagreement with the Law of War Manual on targeting civilians employed in or on military objectives.)

Whatever one might think about these positions individually, putting the US’s forward-leaning position on targeting war-sustaining objects together with the Manual’s position on assumption of risk by civilians in the vicinity of legitimate military targets, creates a toxic brew: Civilians who are not only in, but are simply near legitimate military targets — including not only terrorist safe houses hidden in residential neighborhoods, but also oil production facilities, oil tankers, banks, and other engines of economic activity that might be war-sustaining — no longer count for proportionality analysis. It is hard for me to believe that this is the result the DOD intends, but this is the logical implication of its public positions. And even if the DOD does not intend to act on it, other states — now licensed by the US interpretation of the guiding law — may not have the same compunctions.

The Manual threatens to upend proportionality, not just for the brave MSF doctors working in conflict zones, but for all the unfortunate civilians who live there. It is time for it to change.