Dilemma of Proportionality in International Humanitarian Law

International Humanitarian Law is a set of rules made for regulating armed conflicts that seek to limit the effects of armed conflict, by protecting the persons who are not the part of the armed conflict. Proportionality is one of the pillars of International Humanitarian Law and an inherent part of customary international humanitarian law, which prohibits attack causing excessive incidental loss to civilians and damage to civilian objects than an expected military advantage. This principle acknowledges such inevitable collateral civilian casualties and damage to civilian objects caused even after taking reasonable care and precautions in attack by the parties of the armed conflict. Usually, caused when civilians and civilian objects are mingled with combatants and military objectives.  

According to this principle before attacking, an assessment should be done comparing incidental loss or damage from the attack and the advantage from the attack which can be expected by a reasonable person while planning or launching the attack, according to the information possessed by him at the relevant time. As stated in Prosecutor v. Prlić, principle of proportionality is defined in Article 51(5)(b) of Additional Protocol 1 of Geneva Convention 1949 and was later drawn by the drafters of Rome Statute of International Criminal Court for Article 8(2)(b)(iv) as War Crime of causing excessive incidental damage civilian objects and loss to civilians.

However, as there is no proper standard of measuring proportionality and the assessment is done on the expectation of the commander which makes it very subjective and prone to ambiguities. Furthermore, the cost of any erroneous judgment is very high because it can result into death of civilians and damage to civilian objects. Hence, there is a need for modification in this standard of proportionality.

Problems in assessing Incidental loss

Proportionality operates in the scenario in which incidental injury and damage is foreseeable, albeit undesired. Incidental loss includes injury, casualties and damage which the person planning the attack could expect. Incidental loss consists of both direct and indirect effects. Direct effects are the immediate, first-order consequences whereas indirect effects of an attack consists of the reverberated, delayed and displaced (second, third and higher-order) consequences of the action.

The incidental damage considered in proportionality assessment includes any indirect loss that may be reasonably expected and foreseeable by those launching or planning the attack. So if a commander concludes in good faith based on the information reasonably available that the incidental damage to civilian or civilian object is not excessive, the attack will not be in violation of the prohibition even if an ex post facto assessment reveals that excessive incidental damage has been inflicted. 

However, it is a contentious issue that up to what extent( i.e. upto what order) the effects of the attack have to be factored into the proportionality test. Moreover, the foreseeability of the person may also vary depending on the planning of the attacks, for example, the attacks done in defence will not be planned and the expectation of incidental loss will vary as compare to the well planned bombings. Regardless of what the possible losses are, as proportionality is assessed from the expectation of the commander hence, commander has the complete discretion to attack unless the attack is clearly disproportionate.

 Problems in assessing Military Advantage

The assessment of proportionality requires balancing of two very different sets of values and objectives. The two values are expected incidental loss and the concrete and direct military advantage which can be anticipated from the attack. The expression, “concrete and direct” is intended to show that the advantage concerned should be substantial and relatively immediate, hence the advantage which is hardly perceptible or which would only appear in the long-term should be disregarded.

Proportionality is calculated on the expectation rather than the results and the military advantage factored into this standard is determined at the time of planning or executing an attack (Commentary on HPCR manual). Thus, it means that foreseeable incidental damage, or casualties should be weighed against the foreseeable military advantage of a particular military operation including indirect effects.

However, it is not necessary that the concrete and military advantage anticipated must be the advantage of destroying or weakening the enemy’s armed forces but can also be that of the denying enemy military object and defending one’s own attacking force (DoD Law of War Manual).  In anticipation of military advantage the same prospective standard is applied which is applicable in expectation of incidental loss, hence it gives the commander the same discretion for estimating military advantage, as for incidental loss, which may vary from person to person according to the importance of the military objectives .

Problem in assessing the proportionality

As stated in Prosecutor v Galić there exists a basic obligation to spare civilians and civilian objects as much as possible and this obligation guides the attacking party while considering the proportionality. The assessment should include military advantage and incidental loss in terms of relatives values which will be included or excluded in totalling the sums, in the standard of time or space and according to the extent a military commander is obligated to expose his forces to danger to limit the incidental loss. 

Assessment of proportionality requires balancing of two very different sets of values and objectives, in a framework in which all choices will affect human life. That balancing is inherently difficult, and raises significant moral and ethical issues and raises core questions, in assessing a commander’s decision to attack like (a) whether he or she made the determination based on the best information available, given the circumstances, (b) what to include or exclude in totalling of sums (indirect effects), (c) what are the relative values to be assigned to the military advantage and incidental loss to civilians and civilian objects ,  (d) whether commander took all precautionary measures to spare civilians and civilian objects and (e) whether a reasonable commander could have reached a similar conclusion.

            The answer to these questions may differ depending on the background and values of the commander. Moreover, International Humanitarian Law lacks the definition of the term ‘excessive’ and thus, works on the general agreement that ‘excessive’ is not equivalent to ‘extensive’ and that assessing excessiveness is more than an empirical analysis. Assessment of the proportionality principle is not a matter of counting civilian casualties and comparing them to the number of enemy casualties. Hence, even extensive civilian casualties may not be excessive in the light of the concrete and direct military advantage anticipated. However, there is no standard for determining proportionality and as proportionality is estimated ex-ante therefore it becomes very subjective and difficult for anyone,  facing an immense pressure of armed conflict, to determine whether attack is proportionate or not.

Consequences of this problem

Firstly- Article 8(2)(b)(iv) of Rome Statute which criminalizes disproportionate attacks during armed conflicts, requires an evaluation by the Court based on the information available to the perpetrator. Thus judges will have to decide whether the attack is proportionate or not, from reasonable commander standard, according to the information available to him at the time. Also, according to Article 66 of Rome Statute, the onus is on the prosecutor to prove the guilt of the accused beyond reasonable doubt and until then the commander is presumed to be innocent. Hence, both the court and the prosecutor has to inspect the expectation of the commander retrospectively, which because of ambiguities and varied interpretation can make accused go scot-free.

Secondly- This proportionality principle justifies civilian deaths and damage to civilian objects, though not directly, if the commander thinks that the loss is not excessive. This facet of this principle is contrary to the rule of distinction by which parties to the conflict are obligated to distinguish between civilians and combatants, and civilian objects and military objects.  


The International Humanitarian Law seeks to limit the effects of armed conflicts on civilians and civilian objects by making an obligation on the parties of the armed conflict. Hence, laws are biased towards civilians and civilian objects for their protection. Like in case of doubt that whether an object is civilian or military, it shall be presumed to be a civilian object and the objects which are indispensable to the survival of the civilian population should not be attacked.

Similarly, in case of doubt i.e. in the situations where it cannot be clearly said whether attack is proportionate or not. The attack should be presumed to be disproportionate and the onus should be on the military commander to prove that the attack was proportionate, and that he acted reasonably according to the information available to him. As proportionality is assessed according to the expectation of the commander hence if he is innocent he will be able to justify it. Moreover, this will create deterrence as now commander will have to justify his assessment, and will have to take more precautions while attacking, and in dubious cases he has to refrain from attacking which will reduce incidental losses.

The author is a 2nd Year Student of GNLU, Gandhinagar