The Principle of Proportionality in Armed Conflict

Reverberating effects of war as part of the proportionality equation Reverberating effects of war as part of the proportionality equation ©

24 September 2018

Proportionality in attacks: an indefinite via media between humanity and military necessity.

Determining whether civilian harm caused by a particular attack constitutes a violation of International Humanitarian Law (IHL) is rarely a straightforward matter and the reason is twofold. Firstly, commander’s knowledge of facts on the ground at the time of the attack are rarely made public. Secondly, the rules governing the conduct of hostilities are formulated in such a general and often flexible way, taking account of operational realities, that they easily become subject to divergent understandings.

In theory, the object and purpose of the rules governing the conduct of hostilities under IHL is the protection of civilians and civilian objects, by establishing an appropriate balance between two competing principles: military necessity and considerations of humanity. Unfortunately, reality shows how precarious and subjective this balance can be. And nowhere is this subjectivity more evident than in the practical application of the principle of proportionality.

To further explore this topic and better understand the critical relationship between military necessity and considerations of humanity, in June 2016, the International Committee of the Red Cross (ICRC) and Université Laval jointly organised an International Expert Meeting, gathering practitioners from 16 different countries. The Expert Meeting yielded a comprehensive Report, published in September 2018. Starting from concrete given scenarios, the Report contains crucial reflections of the participants and presents some essential recommendations for the future implementation of the proportionality principle.

According to IHL, combatants must direct their operations solely against military objectives. It follows that intentionally directing attacks against civilians and civilian objects is prohibited and constitutes a war crime under International Criminal Law (ICL).

However, an attack directed against a legitimate military target may still result to be unlawful. That scenario occurs when the two fundamental principles of distinction and proportionality are not respected.

In practice, the principle of distinction seeks to spare civilians from harm to the greatest extent possible, by requiring those who plan or launch an attack take all feasible precautions to verify that the objectives attacked are neither civilians nor civilian objects. Then, once the military character of a target has been ascertained, proportionality brings into the equation a new element: commanders must consider whether striking this target is expected to cause incidental loss of life, injury to civilians, damage to civilian objects or a combination thereof, which would be excessive, and thus disproportionate, in relation to the concrete and direct military advantage anticipated.

Consequently, depending on the circumstances, incidental civilian harm may be either lawful or unlawful. It may be lawful – albeit regrettable – where all feasible precautions had been taken to avoid or at least minimize the harm, and where this harm was not expected to be excessive compared to the concrete and direct military advantage anticipated. It can only be lawful if these two conditions are fulfilled.

The truth is, however, that both the concepts of “excessive harm” and “concrete and direct military advantage” are necessarily undefined and subject to different interpretations. Thus, as fighting increasingly takes place in densely populated areas, where incidental harm is likely to occur due to the co-location and intermingling of lawful targets and protected persons and objects, the principle of proportionality is more crucial than ever in current armed conflicts.

Interesting points of discussion related, for instance, the reverberating effects of attacks conducted in densely populated areas or the applicability of the proportionality principle in case of dual-use objects, which are particularly common in urban warfare. Dual-use objects are civilian objects that temporarily become military objectives because they are simultaneously used for military purposes and vice versa (a building, a bridge or an electricity station, for example). From a legal perspective, however, an object is either a military objective or a civilian object. No intermediate categories are encompassed. It follows that, if a minor military use has turned a civilian object into a military objective, the damage caused to the remaining civilian part – however important it is – would have no bearing on the decision to launch an attack.

This view has been strongly criticized by experts and the ICRC, according to which the impact of the attack on the civilian part of a dual-use object must always be taken into consideration in the assessment of proportionality. In other words, the destruction of a bridge, considered as a legitimate military target, may be disproportionate if it the result makes it impossible for civilians to get food or medical supplies, thus resulting in a serious deterioration of the humanitarian situation.


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by Federica Pira
Editing by Calum McLanachan

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