This article is the latest in our Fog of Law series that examines the gray zones in international law and conflict that can be exploited by states. The series comes in advance of an expert workshop on the topic at the US Naval War College’s Stockton Center that Just Security is cosponsoring with the Naval War College and the International Committee of the Red Cross.

In the early morning of September 21, 2015, coalition airstrikes destroyed the homes of the Razzo family in Mosul, Iraq. The airstrikes killed Mayada, Tuqa, Najib, and Mohannad. Basim survived, but lost his wife, daughter, son, and brother.

According to a partially redacted coalition report, their homes were targeted based on intelligence reports, the most recent one in August, indicating that ISIL was using a building located adjacent to the targeted villas. Apparently, “given there is a one road access to these facilities it was possibly assessed that they were connected and both used by ISIL.” Drone surveillance totaled 95 minutes, spread over three days, collected in the late afternoon, evening, and lunchtime. The footage showed unarmed adult men opening and closing the front gate for arriving vehicles, while no adult women or children were observed. According to the coalition, this was not evidence of “domestic activity,” but instead of “access control.” The report describes the outcome as tragic but determines that the targeting process remains sound. While a pre-strike legal review remains redacted, the report concludes that the coalition conducted the strike in accordance with the law of armed conflict.

In my view, the facts disclosed in the report do not support the conclusion that the strike conformed to the law of armed conflict. Instead, these facts may support a different conclusion, namely that the strike conformed to the law of armed conflict as understood by the United States Department of Defense. As I explain at greater length elsewhere, there is a gap between the law as it is and the law as the Defense Department understands it. The Razzo family may have fallen into that gap, and they may not have fallen alone.

In their awardwinning article, “The Uncounted,” journalists Azmat Khan and Anand Gopal investigated over 100 coalition airstrikes across northern Iraq between April 2016 and June 2017. The authors found that one in five of the coalition strikes killed civilians, a rate more than 31 times that acknowledged by the coalition. According to the authors, “[w]hile some of the civilian deaths … were a result of proximity to a legitimate ISIS target, many others appear to be the result simply of flawed or outdated intelligence that conflated civilians with combatants. In this system, Iraqis are considered guilty until proved innocent.”

Killing in the Fog of War

Ambiguity pervades the conduct of hostilities. Combatants must make targeting decisions based on incomplete information that reasonable people may interpret in different ways. Recognizing this inescapable reality, international law provides two rules to guide combatants in the fog of war.

First, the target verification rule, as formulated in Protocol I to the Geneva Conventions, provides that

those who plan or decide upon an attack shall … do everything feasible to verify that the objectives to be attacked are neither civilians nor civilian objects and are not subject to special protection but are military objectives

Regrettably, the United States is not one of the 174 state parties to Protocol I. However, the target verification rule now reflects customary international law, binding on all states, according to the International Committee of the Red Cross as well as distinguished military lawyers.

Nothing in the coalition report suggests that further surveillance of the Razzo family homes was not feasible, that is, not “practicable or practically possible, taking into account all circumstances ruling at the time, including humanitarian and military considerations.” There is no suggestion that coalition forces were at risk, that ISIL fighters or equipment were about to escape, that surveillance assets were needed elsewhere, or that other military considerations required coalition forces to stop seeking more information and act on the limited information available.

The aim of verifying that a person or object is not civilian but military may seem redundant. After all, with a few qualifications, these are mutually exclusive categories. Yet the coalition report illustrates the wisdom of the rule. According to the report, “[w]hilst no overtly nefarious activity was observed, what was observed did fit with the target characterization due to evidence of access control and the expectation that groups of ADM would be observed at the target.” At the same time, “the fact that weapons were not observed would not have been considered unusual” because “[p]articularly at headquarter and safehouse locations, ISIL does not obviously brandish weapons to remain from being detected.”

In other words, the presence of unarmed adult men opening a gate was consistent with the target being military. In contrast, the target verification rule requires attackers to seek evidence that is inconsistent with the target being civilian. Evidence that is equally consistent with both military and civilian status—like unarmed adult men opening a gate—moves one no closer to target verification. According to the report, surveillance “may not have provided confirmed evidence of ISIL,” but “[w]hat was observed in the small amount of [surveillance] provided a level of confidence that [redacted] was accurate.” Such false confidence is precisely what the target verification rule aims to dispel.

The coalition report found “no evidence indicating carelessness or bad faith.” In my view, we should understand carelessness in objective terms, as failing to take all feasible precautions to avoid or minimize harm to civilians. Instead, the report seems to understand carelessness in subjective terms, finding “nothing to indicate that those involved in validating this target gave less than their full effort to minimize the risk to non-combatants while accomplishing the mission.” However, in my view, the report contains nothing to indicate that those involved gave the effort required by international law.

At the same time, it is possible that the coalition complied with international law as understood by the United States Department of Defense. After all, the 1236-page U.S. Department of Defense Law of War Manual does not discuss the target verification rule even once: not to accept it as reflecting customary law, not to reject it as reflecting only treaty law, and not to provide an alternative approach. This puzzling omission seems even more startling when one recalls that the U.S. Army’s Law of Land Warfare Field Manual, required that attackers “must take all reasonable steps to ensure … that the objectives are identified as military” in 1956, anticipating the canonical formulation of Protocol I by two decades. In this light, the 1956 Army Manual looks like a progressive document, while the 2015 DoD Manual looks regressive.

Astonishingly, the Manual does not include target verification among its illustrative list of ‘feasible precautions in planning and conducting attacks’. Notably, the category of ‘assessing the risks to civilians’ focuses on risks of incidental harm to civilians in or near military targets, not risks of mistakenly targeting civilians or civilian objects. (Ryan Goodman suggested to me that one explanation may be that the Manual rather idiosyncratically treats the precautions rule as a corollary of the proportionality principle, which is concerned with incidental harm rather than direct targeting).

Importantly, in a section entitled “Assessing Information Under the Law of War,” the Manual states that

Decisions by military commanders or other persons responsible for planning, authorizing, or executing military action must be made in good faith and based on their assessment of the information available to them at the time.

As the section heading suggests, this provision tells combatants to assess the information available to them, not to gather as much information as practically possible. Accordingly, while this provision may supplement the target verification rule, it cannot supplant the target verification rule.

It is trivially true that after combatants do everything feasible to verify that a target is not civilian but military, they should then assess the information made available to them by their verification efforts. And it is trivially true that combatants should make targeting decisions in good faith. Such trivial truths provide no guidance to combatants and no protection to civilians.

In fact, international law already supplements the target verification rule with a second rule that tells combatants what to do after doing everything feasible to verify that a target is not civilian but military.

The rule of doubt, as formulated in Protocol I, provides with respect to persons that

In case of doubt whether a person is a civilian, that person shall be considered to be a civilian

and provides with respect to objects that

In case of doubt whether an object which is normally dedicated to civilian purposes, such as a place of worship, a house or other dwelling or a school, is being used to make an effective contribution to military action, it shall be presumed not to be so used.

The rule of doubt also reflects customary international law, according leading military lawyers from around the world.

Regrettably, the Manual flatly rejects the rule of doubt, asserting that

Under customary international law, no legal presumption of civilian status exists for persons or objects, nor is there any rule inhibiting commanders or other military personnel from acting based on the information available to him or her in doubtful cases.

In place of the rule of doubt, the Manual again requires only a good faith decision:

In assessing whether a person or object that normally does not have any military purpose or use is a military objective, commanders and other decision-makers must make the decision in good faith based on the information available to them in light of the circumstances ruling at the time.

The scope of this subjective standard is limited only at the margins, by the proviso that

Attacks … may not be directed against civilians or civilian objects based on merely hypothetical or speculative considerations regarding their possible current status as a military objective.

Arguably, the coalition airstrike on the Razzo family homes was based on speculative and hypothetical considerations regarding their possible current status, namely that the homes were on the same road as a building that ISIL had used weeks or months earlier. On these shaky grounds, “it was possibly assessed that [the homes] were connected [to the building] and both used by ISIL.” (I assume that this rather awkward phrase means that it was assessed that the homes were possibly—as opposed to certainly—connected to the building.)

More importantly, the decision to attack the Razzo homes, based on the information available in light of the circumstances ruling at the time, violates any plausible interpretation of the rule of doubt. Admittedly, states and scholars interpret the rule of doubt in somewhat different ways. In this sense, a rule intended to address factual ambiguity in the conduct of hostilities introduces some additional legal ambiguity into the conduct of hostilities. Fortunately, the rule’s humanitarian value makes its careful interpretation a challenge well worth undertaking.

How much doubt regarding a person or object’s legal status precludes lawful attack of that person or object? While many Protocol I state parties simply incorporate its terms, the Netherlands adds the following:

If there is any uncertainty whether someone is a genuine civilian, this person is given the benefit of the doubt pending proof to the contrary, and must be treated as a civilian.

On this view, the required level of certainty is both high and fixed, that is, it does not vary with the circumstances. Spain adopts a similar “any doubt” standard. So does the Special Court for Sierra Leone. Obviously, the available evidence hardly established beyond any doubt that the Razzo house was military.

In contrast, France and the United Kingdom take the view that the rule of doubt applies only

in cases of substantial doubt still remaining after the assessment [of the information from all sources which is reasonably available to military commanders at the relevant time] has been made, and not as overriding a commander’s duty to protect the safety of troops under his command or to preserve his military situation.

In other words, substantial doubt regarding a person or object’s legal status precludes lawful attack unless refraining from attack will jeopardize troop safety or positional advantage. Since there was substantial doubt that the Razzo houses were military rather than civilian, and the report does not indicate that attacking the houses was necessary to protect troops or preserve military positions, the attack seems to violate this interpretation of the rule of doubt as well.

Alternatively, the ICRC takes the view that the level of doubt sufficient to preclude attack varies with the circumstances, reflecting the shifting balance of humanitarian considerations against attack and military considerations in favor of attack. If the potential military value of the suspected target is low, while the potential harm to civilians or civilian objects is high, then “substantial doubt” or even “any doubt” may suffice to preclude attack. Conversely, if the potential military value of the suspected target is very high, while the potential harm to civilians or civilian objects is very low, then only grave doubt may suffice to preclude attack.

Based on the coalition report, it seems that there was more than enough doubt to preclude attacking the Razzo houses. On one side of the scales lay the risk of mistakenly destroying two civilian homes, killing at least seven adult male civilians, and possibly killing more civilians inside. On the other side of the scales lay the risk of mistakenly sparing two buildings that ISIL may have used in the past, whose potential military value the report does not bother to describe, but which had been spared for weeks without any military disadvantage worth mentioning. Balancing the risks of error in both directions, it seems that the required level of certainty was quite high, and not met by the information available at the time of the attack.

Finally, many leading military lawyers take the view that

The degree of doubt necessary to preclude an attack is that which would cause a reasonable attacker in the same or similar circumstances to abstain from ordering or executing an attack.

Presumably, the reasonable attacker will consider the potential harm to civilians and civilian objects, the potential military value of the target, troop safety, and tactical position. Accordingly, the “reasonable attacker” standard should converge with the alternatives described above, and the attack on the Razzo family homes should be considered unreasonable in the circumstances.

My own view has two parts. First, at a minimum, attackers must reasonably believe that their target is not civilian but military, based on a clear preponderance of reliable evidence. Second, above that minimum threshold, the required level of certainty varies with the potential harm to civilians and civilian objects of an erroneous attack and the potential military value of the suspected military target. In my view, the evidence that the Razzo homes were not civilian but military did not meet the minimum threshold. As we have seen, the report does not even bother to describe what potential military value the coalition perceived, let alone explain how that potential value justified the risk of erroneously targeting civilian homes and killing those inside.


I cannot say definitively that the coalition airstrike that killed Mayada, Tuqa, Najib, and Mohannad violated the law of armed conflict. Parts of the coalition report are redacted, and the original intelligence reports apparently remain classified. Similarly, I cannot say definitively that they died because the Department of Defense ignores the target verification rule and rejects the rule of doubt. Perhaps the redacted pre-strike legal review applied equivalent rules, either as a matter of law or under applicable rules of engagement. Or perhaps international law, no matter how reasonably interpreted or carefully applied, could not have saved their lives. But somewhere in Iraq or Syria, Yemen or Afghanistan, there are men, women, and children whose lives will one day depend on how we resolve the ambiguity that pervades armed conflict. We owe it to them to do better.