The Practical Guide to Humanitarian Law

« Calling things by the wrong name adds to the affliction of the world. » Albert Camus.

Proportionality

Proportionality is a core legal principle that exists at all levels of international and domestic law. It provides that the legality of an action is determined by the respect of the balance between the objective and the means and methods used as well as the consequences of the action. This principle implies an obligation to assess the context before deciding on the legality or the illegality of an action. The assessment of the proportionality is the responsibility of those who act and must be carried out proactively before action is taken. In case of dispute or doubt, courts may assess the legality and proportionality of facts a posteriori .

Proportionality is also a rule and a fundamental principle of international humanitarian law (IHL) applicable in situations of armed conflict (I). It requires a balance to be struck between military necessity and the protection of civilians when assessing the legality of any attack. Respect for the principles of distinction, precaution and proportionality is a core duty of military commanders when conducting the hostilities and ordering attacks. It may trigger their individual criminal responsibility for possible war crimes. ➔ AttackDuty of commanders

Proportionality is also instrumental in human rights (II) and criminal law (III). It applies in cases of individual or collective self-defence. It applies in situations of internal disturbance when the State resorts to extraordinary emergency legislation and measures restricting human rights in order to restore public order and security. It requires that the derogation from the rule of law be strictly limited and proportionate to the danger, and that the criminal sanctions imposed be proportionate to the gravity of the offence.

I. Proportionality in situations of armed conflicts (IHL)

International law does not authorise States to use armed force except in cases of self-defence or aggression. The branch of international law governing the right to use armed force is commonly referred to as jus ad bellum . Since 1945, it has been enshrined in the Charter of the United Nations and its collective security mechanism. The concept of self-defence allows only military measures that are “proportionate” to the attack and necessary to respond to it.

ReprisalsSelf defence

Jus ad bellum is distinct from the international law applicable to the conduct of hostilities in situations of armed conflict, also known as jus in bello, the law of armed conflict or IHL. Since the adoption of the Geneva Conventions, in 1949, IHL has restricted the means and methods of warfare in all situations of armed conflict, regardless of the just cause or just war claimed by the belligerents. Therefore, the IHL rule of proportionality, which imposes on all military attacks, applies the same way regardless of the just cause pursued in an attack.

Under IHL, the protection of civilians in armed conflict is governed by three fundamental principles: distinction, proportionality and precaution.

The duty of distinction requires parties to an armed conflict to always distinguish between civilian persons and objects and military objectives. However, although IHL prohibits direct attacks on civilians and civilian objects, other attacks on legitimate military objectives may cause damage to civilians and civilian objects. The principle of proportionality regulates the limits of acceptable incidental civilian damage caused by military operations.

Enemy combatants and civilians directly participating in hostilities are therefore not covered by the proportionality principle. Furthermore, those responsible for planning a specific attack must opt for a weapon that mitigates or reduces the potential for civilian collateral damage. They must also conduct a diligent pre-attack assessment to ascertain its potential effects on civilians and civilian infrastructure and prioritise the rapid acquisition, and assessment of target information that should also be constantly updated. Therefore, the legality of such an attack should rely on an honest evaluation of the facts and circumstances known to commanders at the time of planning, rather than on hindsight.

IHL prohibits attacks that are likely to cause “incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated” (API, arts. 51(5)(b) and 57(2)(a)(iii)). This prohibition, originally codified in Additional protocol I to the Geneva conventions, is now part of customary IHL (CIHL, rule 14). This principle is therefore binding on all States and parties to international and non-international armed conflicts.

This rule of IHL has also been incorporated into international criminal law (ICL) through the Rome Statute of the International Criminal Court (ICC). Indeed, the definition of a war crime provided in the Rome Statute includes the act of “intentionally launching an attack in the knowledge that such attack will cause incidental loss of life or injury to civilians or damage to civilian objects or widespread, long-term and severe damage to the natural environment which would be clearly excessive in relation to the concrete and direct overall military advantage anticipated” (art. 8(2)(b)(iv) of the Rome Statute). This prohibition has also been confirmed by the jurisprudence of international criminal tribunals, particularly in non-international armed conflicts. ( infra , Jurisprudence).

The rule of proportionality requires the comparison and balancing of elements of different nature, namely the military advantage sought on the one hand, and the damage and civilian losses associated with it on the other. IHL provides no objective standard for assessing what constitutes excessive civilian harm in relation to a given military advantage. The ICRC commentaries to Additional protocol I make it clear that the purpose of such a principle is precisely to oblige armed forces or groups to determine where such limits lie in each situation (para. 2206). The wording of the rule is clear enough for a criminal court to apply it a posteriori . The challenge lies in the proactive and prospective determination of the proportionality test by military commanders deciding whether or not to authorise an attack.

The IHL formulation of the rule of proportionality requires a balancing of the foreseeable civilian harm and the expected military advantage based on the knowledge available to the military commander at the time prior to the initiation of an attack. This means that commander must assess the risk of foreseeable civilian casualties and damages in the context of a given attack and before it, and take all precautions to avoid or at least minimise such civilian harm. It is also their duty to determine that these foreseeable civilian casualties and damages remain proportionate to the military advantage they expect to obtain from a given attack. This proportionality test requires that commanders have a clear appraisal before the attack of the expected military advantage and of the related foreseeable civilian losses to decide if they are commensurate. As a result, civilians’ casualties that occur during an attack, while satisfying the proportionality test, would be tantamount to intentional civilian deaths justified by military necessity. Indeed, they cannot be qualified as mistakes, and even if the death of such civilians is not the aim of the attack, it is a result that was anticipated, accepted, and inflicted by military commanders.

IHL emphasised that the expected military advantage must be concrete and immediate, i.e., substantial and relatively short time rather than long term. Military advantages that are barely perceptible and those that would only appear in the long term should therefore be disregarded in the proportionality test. In military terms, the ICRC commentary to Protocol I as well as CIHL rule 14 emphasise that the proportionality rule must be assessed in relation to the tactical military advantage gained in securing each objective of a precise attack. A global strategic objective, such as winning the war, is not relevant to ensuring the proportionality test, as it would always outweigh the harm to civilians and therefore nullify the proportionality requirement. However, the interpretation of the required military advantage remains an area of tension between IHL and ICL as the definition of war crime in the Rome Statute of the ICC refers to the overall military advantage. This tension is also fuelled in numerous contexts, such as armed conflict against alleged terrorist groups where the just cause of the war tends to outweigh IHL rules on the protection of civilians in the conduct of hostilities.

Translating proportionality assessment into military practice requires guidance on how to solve the equation that compares values that are not directly commensurable. In mathematical terms, it can be written as follows: x expected civilian harm < expected concrete and direct military advantage . The value of civilian deaths has been elaborated through specific mechanisms put in place by the United States of America (US), the North Atlantic Treaty Organization (NATO) and coalition partners in the wars in Afghanistan and Iraq. The NATO Civilian Casualty Assessment (CASS) functioned as post-facto investigation mechanism of civilian deaths in relation to NATO military operations. Collateral Damage Estimation (CDE) is the name given to the process used by the US and other NATO militaries. The concept of Non-combatant Casualty Cut-off Value (NCV) was also developed as a tool to objectively quantify proportionality. This NCV would depend on the high or low value of the military target under attack -ranging from 0 civilian deaths to 30 for someone like Osama Bin Laden. Reference to NCV as a direct translation of the proportionality requirement has been included in numerous Rules of Engagement (ROE). ROE and NCV are classified military documents. Access to such documents is restricted in most countries of the world. However, the existence of the US and NATO practices has been made public through various investigative processes. For example, the NCV was officially abandoned in the US in 2018 and replaced by the Pentagon’s Civilian Harm Mitigation Response Action Plan in 2023. The aim was to restore the obligation to avoid or minimise civilian harm, rather than to set an ‘acceptable’ threshold of civilian casualties that could be perceived as a licence to kill.

☞ Proportionality is one of the key principles and rules of IHL relating to the protection of civilians in the conduct of hostilities. It enables and promotes a concrete debate on the limitations of military action and the space that must be left for the protection of civilians and humanitarian action in situations of armed conflict. It balances the conflicting interests of military necessity and the laws of humanity. This rule allows certain forms of suffering to be qualified as unnecessary or excessive, while others are justified by precise military necessity. It reflects the fact that IHL prohibits suffering that is not directly related to, or disproportionate to, a concrete military advantage.

The proportionality of a reprisal to the initial attack is the element that distinguishes a reprisal, which is acceptable IHL from an act of revenge, which is always prohibited. IHL clearly establishes the responsibility of military commanders to respect this principle.

The interpretation and practical implementation of the principle of proportionality is the cornerstone of all rules relating to the protection of civilians in armed conflict. However, the natural military tendency is to limit the scope and legal value of what is perceived as a constraint on military operations and a threat to the criminal responsibility of commanders.

Proportionality is particularly important in densely populated areas, where the distinction between military targets and civilians is complex and the potential for civilian collateral damage is high. It also plays a key role in the legality of attack of target that have a civilian and military dual use. It must be recalled that the proportionality requirement is not satisfied by warning civilians to leave the area of military operations. Indeed, effective advance warning is provided by IHL as a separate and additional precaution to be taken when an attack may affect the civilian population (API, art. 57(2)(c) and CIHL, rule 20). However, it cannot replace the other precautionary and proportionality requirements imposed by IHL for the protection of civilians in the conduct of hostilities.

Military challenges to the interpretation and implementation of proportionality in situations of armed conflict demonstrate the need to strengthen national and international judicial review of military doctrine and manuals on this point.

A tragic example of this necessity can be found in the war launched by Israel in Gaza in retaliation for the Hamas attack on Israel on 7 October 2023. In fact, Israel’s claim to respect IHL wrongly uses the overall strategic objective of its war to globally “justify” the alleged proportionality of massive civilian deaths and destruction.

AttacksCiviliansDuty of commandersInternational Criminal CourtMethods (and means) of warfareMilitary necessityMilitary objectivesProtected objects and propertyReprisalsWar

II. Proportionality of Restrictions to Human Rights in Situations of Internal Disturbances and Tension

The question of the proportionality of restrictions on human rights imposed by a State in the name of national security or the defence of public order arises in many situations such as internal disturbances or the fight against terrorism, situations where the intensity of violence does not trigger the application of IHL. International human rights conventions and national or regional courts therefore have a role to play in recalling the context and content of the proportionality requirement in such situations.

Jurisprudence indicates that human rights continue to apply in these situations, subject to derogations made by States in accordance with the procedures provided for that purpose. The jurisprudence also indicates that, in these circumstances, decisions taken by the executive remain subject to the control of national and international judges. The latter retain the ultimate authority and responsibility to assess the reasonableness and proportionality between the restriction of individual rights and the argument of “necessity” used by the government to justify its action ( infra , Jurisprudence).

Fundamental guaranteesHuman rightsInternal disturbances and tensions

III. Proportionality of Sanctions in criminal law

Proportionality is also used in relation to fundamental judicial guarantees to ensure that the punishment fits the crime. This is reflected in the Geneva Conventions, which state that “the courts [of the occupying power] shall apply […] the principle that the penalty shall be proportioned to the offence […]” (GCIV, art. 67).

Fundamental guarantees

Jurisprudence

Various international tribunals have applied the principle of proportionality in cases relating to the conduct of hostilities, military reprisals or human rights (1-5). Judgements of the Israeli Supreme Court also help to clarify the scope and application of this principle (6).

1. The International Court of Justice (ICJ)

The ICJ recalled that “self-defence […] warrant[s] only measures which are proportional to the armed attack and necessary to respond to it, a rule well established in customary international law” ( Military and Paramilitary Activities in and against Nicaragua [Nicaragua v. United States of America], Merits, Judgment , I.C.J. Reports 1984, p. 14, para. 176).

In their submissions to the ICJ in the Nuclear Weapons case, numerous States, including States not party to Additional protocol I, or not party to it at the time, invoked the principle of proportionality in assessing of whether a nuclear weapons attack would violate IHL. In its 1996 Advisory Opinion on the legality of the use of nuclear weapons, the Court recognised the applicability of the principle of proportionality in situations of self-defence and armed conflict. It recalled that there is a “specific rule whereby self-defence would warrant only measures which are proportional to the armed attack and necessary to respond to it, a rule well established in customary international law”. It also affirmed that “a use of force that is proportionate under the law of self-defence, must, in order to be lawful, also meet the requirements of the law applicable in armed conflict which comprise in particular the principles and rules of humanitarian law and the duty to assess whether an action is in conformity with the principles of necessity and proportionality” (paras. 41-44). In his separate opinion, Judge Higgins further held that “the principle of proportionality, even if finding no specific mention, is reflected in many provisions of Additional Protocol I to the Geneva Conventions of 1949. Thus, even a legitimate target may not be attacked if the collateral civilian casualties would be disproportionate to the specific military gain from the attack” ( Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion , I.C.J. Reports 1996, paras. 41-44, p. 245 and, Dissenting Opinion of Judge Higgins , para. 20, p. 587).

2. The International Criminal Tribunal for the Former Yugoslavia (ICTY)

According to the ICTY, the principle of proportionality means that the incidental and involuntary harm caused to the civilian population during a military attack must not be excessive in relation to the direct military advantage gained.

In the Kupreškić case, the ICTY Trial Chamber referred to the principle of proportionality in the context of military reprisals and the conduct of hostilities. With regard to proportionate reprisals the Trial Chamber affirmed that “even when considered lawful, reprisals are restricted by; (a) the principle whereby they must be a last resort in attempts to impose compliance by the adversary with legal standards (which entails, amongst other things, that they may be exercised only after a prior warning has been given which has failed to bring about the discontinuance of the adversary’s crimes); (b) the obligation to take special precautions before implementing them (they may be taken only after a decision to this effect has been made at the highest political or military level; in other words they may not be decided by local commanders); (c) the principle of proportionality (which entails not only that the reprisals must not be excessive compared to the precedent unlawful act of warfare, but also that they must stop as soon as that unlawful act has been discontinued) and; (d) ‘elementary considerations of humanity’ […]” ( Prosecutor v. Kupreškić et al. , Case No. IT-95-16-T, Judgment , 14 January 2000, para. 535 ( Kupreškić Judgment ).

Regarding the conduct of hostilities, the Trial Chamber stated in the same case that “it is nevertheless beyond dispute that, at a minimum, large numbers of civilian casualties would have been interspersed among the combatants. The point which needs to be emphasised is the sacrosanct character of the duty to protect civilians, which entails, amongst other things, the absolute character of the prohibition of reprisals against civilian populations. Even if it can be proved that the population of Ahmici was not entirely civilian but comprised some armed elements, still no justification would exist for widespread and indiscriminate attacks against civilians. Indeed, even in a situation of full-scale armed conflict, certain fundamental norms still serve to unambiguously outlaw such conduct, such as rules pertaining to proportionality.” ( Kupreškić, Judgment, para. 513). It also reaffirmed that:

“[i]n the case of attacks on military objectives causing damage to civilians, international law contains a general principle prescribing that reasonable care must be taken in attacking military objectives so that civilians are not needlessly injured through carelessness. This principle […] has always been applied in conjunction with the principle of proportionality, whereby any incidental (and unintentional) damage to civilians must not be out of proportion to the direct military advantage gained by the military attack. In addition, attacks, even when they are directed against legitimate military targets, are unlawful if conducted using indiscriminate means or methods of warfare, or in such a way as to cause indiscriminate damage to civilians. These principles have to some extent been spelled out in Articles 57 and 58 of the First Additional Protocol of 1977. Such provisions, it would seem, are now part of customary IHL, not only because they specify and flesh out general pre-existing norms, but also because they do not appear to be contested by any State, including those which have not ratified the Protocol. Admittedly, even these two provisions leave a wide margin of discretion to belligerents by using language that might be regarded as leaving the last word to the attacking party. Nevertheless, this is an area where the ‘elementary considerations of humanity’ rightly emphasized by the International Court of Justice […] should be fully used when interpreting and applying loose international rules, on the basis that they are illustrative of a general principle of international law.” ( Kupreškić, Judgment , para. 524).

In 2000, following the NATO bombing campaign against the Federal Republic of Yugoslavia, the ICTY Prosecutor set up a special committee to review possible war crimes committed by NATO. In the conclusion of its review, the ICTY acknowledges that it may be easier to state a general principle of proportionality than to apply it to a specific situation because of the need to balance different values and quantities. In the NATO bombing campaign against Serbia, the ICTY affirmed that the question of whether the principle of proportionality was respected should be analysed on a case-by-case basis, according to an objective criterion: the assessment of the “responsible command”. Therefore, the ICTY refused to rely on an assessment made by a human rights organisation. Rather, it considered that once the decision to apply the principle of proportionality was taken, the questions that remained unresolved included the following:

What are the relative values to be assigned to the military advantage gained and the injury to non-combatants and/or the damage to civilian objects? What do you include or exclude in totalling these sums? What is the standard of measurement in time or space? To what extent is a military commander obligated to expose his own forces to danger in order to limit civilian casualties or damage to civilian objects? ( Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign against the Federal Republic of Yugoslavia , ICTY, 13 June 2000, para. 49 available at https://www.icty.org/en/press/final-report-prosecutor-committee-established-review-nato-bombing-campaign-against-federal).

In 2013, the ICTY Trial Chamber ruled on proportionality in the context of military necessity in its judgment in the Prlić case. ( Prosecutor v. Prlić et al. , Case no. IT-04-74-T, Judgment, 29 May 2013, paras. 1584 and 1587): “The Chamber therefore holds that although the destruction of the Old Bridge by the HVO may have been justified by military necessity, the damage to the civilian population was indisputable and substantial. It therefore holds […] that the impact on the Muslim civilian population of Mostar was disproportionate to the concrete and direct military advantage expected by the destruction of the Old Bridge.” (para. 1584). It also added: “The Chamber finds by a majority […] that the armed forces of the HVO destroyed the Old Bridge of the town of Mostar, thereby committing the crime of wanton destruction of cities, towns or villages, or devastation not justified by military necessity, a crime recognised by Article 3 of the Statute.” (para. 1587)

3. The International Criminal Court (ICC)

In its decision on the Prosecutor’s request for authorisation to investigate the situation in Georgia at the ICC, the Court identified the use of certain weapons, methods and means of warfare as indicative of an indiscriminate or disproportionate attack. The ICC stressed that civilians and civilian objects were indiscriminately and disproportionately attacked by both Georgian and Russian armed forces through the use of cluster munitions in populated areas, and through the “indiscriminate and disproportionate attacks with aerial, artillery and tank fire strikes against civilians and civilian objects”. ( Situation in Georgia , Case no. ICC-01/15-12-Anx1, Separate opinion of Judge Péter Kovàcs , 27 January 2016, paras. 26-28).

4. The European Court of Human Rights (ECtHR)

The case law of the ECtHR includes an assessment of whether derogations adopted by States from certain rights of the European Convention on Human Rights (ECHR) are proportionate to the aim pursued.

In its judgment in the case of Aksoy v. Turkey , the ECtHR recalled that “it falls to each Contracting State, with its responsibility for ‘the life of [its] nation,’ to determine whether that life is threatened by a ‘public emergency’ and, if so, how far it is necessary to go in attempting to overcome the emergency. […] Nonetheless, Contracting Parties do not enjoy an unlimited discretion. It is for the Court to rule whether, inter alia, the States have gone beyond the ‘extent strictly required by the exigencies’ of the crisis.” Consequently, the derogative measures must be strictly required by the exigencies of the situation ( Aksoy v. Turkey, Application no. 21987/93, Judgment [ Chamber], 18 December 1996, para. 68).

**

  1. The Inter-American Court for Human Rights (IACHR)

In its judgment of 1988, the IACHR affirmed that “regardless of the seriousness of certain actions and the culpability of the perpetrators of certain crimes, the power of the State is not unlimited, nor may the State resort to any means to attain its ends.” (*Velásquez Rodríguez v. Honduras , I/A Court H.R. [Ser. C.], no. 4, 1, Judgment, Merits , 29 July 1988, para. 154).

**6. The Supreme Court of Israel

In a 1999 ruling examining the legality of the use of extraordinary interrogation methods in the context of the fight against terrorism, the Israeli Supreme Court affirmed that neither international nor national law recognised the “necessity defence” for the use of torture or physical means during interrogations in the context of the fight against terrorism. The Court considered that this argument could not authorise the use of physical means to enable investigators to carry out their duties in circumstances of necessity. The Court affirmed that general guidelines for the use of physical means during interrogations must be based on a legal authorisation and not on defences to criminal liability. The “necessity” defence cannot constitute an “ex-ante” basis for rules governing an interrogation (*Public Committee against Torture in Israel v. the State of Israel et al. , HCJ 5100/94, 26 May 1999, paras. 36-37).

**In a 2004 ruling on the legality of the Israeli military’s intervention in Rafah (Gaza Strip), the Israeli Supreme Court acknowledged that the argument of “necessity” can justify a military operation but recalled that such a military operation can be legitimate from a military point of view and still be unlawful. The Court affirmed that judges must examine the legality of military operations through the lens of the principle of proportionality.

Judicial review does not examine the wisdom of the decision to carry out military operations. The issue

addressed by judicial review is the legality of the

military operations. Therefore we presume that the

military operations carried out in Rafah are necessary

from a military viewpoint. The question before us is whether

these military operations satisfy the national and international

criteria that determine the legality of these operations. The fact

that operations are necessary from a military viewpoint does

not mean that they are lawful from a legal viewpoint. Indeed,

we do not replace the discretion of the military commander in

so far as military considerations are concerned. That is his

expertise. We examine their consequences from the viewpoint**

of humanitarian law. That is our expertise. ( Physicians for

Human Rights et al. v. the Commander of IDF Forces in Gaza ,

**HCJ 4764/04, 30 May 2004, para. 9)

**

In a 2005 ruling examining Israel’s policy of targeted killings in the context of the fight against terrorism after the Second Intifada, the Israeli Supreme Court reaffirmed its 1999 jurisprudence on judicial review of the proportionality of derogations. It reaffirmed the need to strike a balance between imperative national security and individual rights: “[n]ot every efficient means is also legal. The ends do not justify the means […] That balancing casts a heavy load upon the judges, who must determine — according to the existing law — what is permitted, and what is forbidden.” ( The Public Committee against Torture in Israel et al. v. the Government of Israel et al ., HCJ 769/02, 11 December 2005, para. 63). The Court recognised that the principle of proportionality is a general principle of international law and one of the core principles of humanitarian law in general, particularly in situations of military occupation (paras. 41 and 42). However, this decision is ambiguous because it creates a distinct category of protected persons per the Geneva Conventions, for the calculation of the proportionality, the one of ‘innocent’ civilians. This introduces a bias within the provisions of IHL, especially in the context of modern armed conflicts with anti-terrorism dimensions. The term ‘innocent civilians’ introduces a criminal element in the determination of the protected status of civilians that can better be established in court of law than in the battlefield. It may feeds general suspicion toward individuals and populations residing under the control of non-state actors labeled as ‘terrorists’. Indeed, they may not be considered as ‘innocent’ civilians under this new categorisation, due to their simple presence and submission to such groups, even if they do not take an active part into the hostilities and refrain from becoming a combatant. . The Court held that:

**[t]he principle of proportionality arises when the military operation

is directed toward combatants and military objectives, or against

civilians at such time as they are taking a direct part in hostilities,

yet civilians are also harmed. The rule is that the harm to

innocent civilians caused by collateral damage during combat

operations must be proportional […] Civilians might be harmed

due to their presence inside of a military target, such as civilians

working in an army base; civilians might be harmed when they

live or work in, or pass by, military targets; at times, due to a

mistake, civilians are harmed even if they are far from military

targets; at times civilians are forced to serve as ‘human shields’

from attack upon a military target, and they are harmed as a

result. In all those situations, and in other similar ones, the rule is**

that the harm to the innocent civilians must fulfil, inter alia , the

**requirements of the principle of proportionality.” (para. 42).

The principle of proportionality applies in every case in which

civilians are harmed at such time as they are not taking a direct

part in hostilities. […] A manifestation of this customary principle**

can be found in The First Protocol , pursuant to which

**indiscriminate attacks are forbidden § 51(4)). (para. 43).

The proportionality test determines that attack upon innocent

civilians is not permitted if the collateral damage caused to them

is not proportionate to the military advantage (in protecting

combatants and civilians). In other words, attack is proportionate

if the benefit stemming from the attainment of the proper military

objective is proportionate to the damage caused to innocent

civilians harmed by it. That is a values based test. It is based

upon a balancing between conflicting values and interests […] It

is accepted in the national law of various countries. It constitutes a central normative test for examining the activity of

the government in general, and of the military specifically, in

Israel. (para. 45).

That aspect of proportionality is not required regarding harm to a combatant, or to a civilian taking a direct part in the hostilities

at such time as the harm is caused. Indeed, a civilian taking part in hostilities is endangering his life, and he might —like a

combatant— be the objective of a fatal attack. That killing is

permitted. However, that proportionality is required in any case

in which an innocent civilian is harmed. Thus, the requirements**

of proportionality stricto senso must be fulfilled in a case in

**which the harm to the terrorist carries with it collateral damage

caused to nearby innocent civilians. […] Performing that

balance is difficult. Here as well, one must proceed case by

case, while narrowing the area of disagreement. Take the usual case of a combatant, or of a terrorist sniper shooting at

soldiers or civilians from his porch. Shooting at him is

proportional even if as a result, an innocent civilian neighbour

or passer-by is harmed. That is not the case if the building is

bombed from the air and scores of its residents and passersby are harmed […] The hard cases are those which

are in the space between the extreme examples. There, a

meticulous examination of every case is required; it is required**

that the military advantage be direct and anticipated ( see

§57(2)(iii) of The First Protocol ). Indeed, in international law, as in internal law, the ends do not justify the means. The

**state’s power is not unlimited. Not all of the means are

permitted […] However, when hostilities occur, losses are

caused. The state’s duty to protect the lives of its soldiers and civilians must be balanced against its duty to protect the l

lives of innocent civilians harmed during attacks on terrorists.

That balancing is difficult when it regards human life. It raises

moral and ethical problems […] Despite the difficulty of that

balancing, there’s no choice but to perform it. (para. 46).

The approach is similar regarding proportionality. The decision

of the question whether the benefit stemming from the

preventative strike is proportionate to the collateral damage

caused to innocent civilians harmed by it is a legal question, the expertise about which is in the hands of the judicial branch. […] Proportionality is not a standard of precision. At times there are a number of ways to fulfil its conditions. A zone of proportionality is created. It is the borders of that zone that the Court guards. The decision within the borders is the executive branch’s decision. That is its margin of appreciation. (para. 58).**

**For Additional Information:

**

Abraham, Yuval, A mass assassination factory: Inside Israel’s calculated bombing of Gaza: Permissive airstrikes on non-military targets and the use of an artificial intelligence system have enable the Israeli army to carry out its deadliest war on Gaza , +972 Magazine, 30 November 2023. Available at https://www.972mag.com/mass-assassination-factory-israel-calculated-bombing-gaza/

Amnesty International, “Federal Republic of Yugoslavia (FRY)/NATO: Collateral Damage” or Unlawful Killings? V iolations of the Laws of War by NATO during Operation Allied Force . Available at https://www.amnesty.org/fr/documents/eur70/018/2000/en/

Cannizzaro, Enzo, “Contextualizing Proportionality: Jus ad Bellum and Jus in Bello in the Lebanese War.”, International Review of the Red Cross , vol. 88, no. 864 (December 2006): 779-792. Available at https://www.icrc.org/en/doc/assets/files/other/irrc_864_cannizzaro.pdf

Dinstein, Yoram, “Collateral Damage and the Principle of Proportionality.” In New Wars, New Laws? , edited by David Wippman and Matthew Evangelista, 211-224. New York: Transnational, 2005.

Gillard, Emmanuella Chiara, Proportionality in the conduct of hostilities: The incidental Harm side of the assessment ; Report; Chatham House. December 2018. Available at https://www.chathamhouse.org/sites/default/files/publications/research/2018-12-10-proportionality-conduct-hostilities-incidental-harm-gillard-final.pdf#page=36

Henckaerts, Jean-Marie and Doswald-Beck, Louise. C ustomary International Humanitarian Law, volume I: Rules , ICRC, 2005. (see rule 14). Available at https://ihl-databases.icrc.org/en/customary-ihl/v1/rule14

ICTY, Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign against the Federal Republic of Yugoslavia . Available at https://www.icty.org/en/press/final-report-prosecutor-committee-established-review-nato-bombing-campaign-against-federal

Institute for Middle East understanding (IMEU), The Dahiya Doctrine and Israel’s use of disproportionate Force , 7 December 2012. Available at https://imeu.org/article/the-dahiya-doctrine-and-israels-use-of-disproportionate-force

Jaworski, Eric, “Military Necessity and Civilian Immunity: Where Is the Balance?” In International Crime and Punishment , Selected Issues, edited by Sienho Yee, 2:87-127. Lanham, MD: University Press of America, 2004.

John-Hopkins, Michael, “Regulating the Conduct of Urban Warfare: Lessons from Contemporary Asymmetric Armed Conflicts.”, International Review of the Red Cross , vol. 92, no. 878 (June 2010): 469-493. Available at https://international-review.icrc.org/sites/default/files/irrc-878-john-hopkins.pdf

Jones, Craig, T he War Lawyers; The United States, Israel, and Juridical Warfare ; 2020, Oxford University Press, 394 pages. Available at https://global.oup.com/academic/product/the-war-lawyers-9780198842927?lang=en&cc=au#

**Lattimer, Mark, Assessing Israel’s Approach to Proportionality in the Conduct of Hostilities in Gaza; Lawfaremedia.org, 16 November 2023. Available at https://www.lawfaremedia.org/article/assessing-israel-s-approach-to-proportionality-in-the-conduct-of-hostilities-in-gaza

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