The International Society for Military Ethics in Europe
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By Ted van Baarda

Much discussion is taking place about whether the Israeli Defence Forces (IDF) are applying proportional violence in Gaza. The question of what amounts to proportional violence remains maddeningly complicated. Neither military ethics nor humanitarian law have been able to define proportionality with satisfactory precision. Before answering the question whether the IDF might be guilty of disproportional violence I will give a brief summary of the complicated conceptual framework. For reasons of space, I will set aside pertinent concepts such as the principle of distinction or the obligation to take precautionary measures.

In IHL the principle of proportionality is mentioned in Article 51 of Additional Protocol I. Although Israel is not a state party to AP I, this does not suggest that it is not bound by proportionality as such. Proportionality is considered to be part of customary law.1 Israel’s Ministry for Foreign Affairs has accepted Article 51 as a “clarification” of customary international law.2 It added that: “[b]y definition, then, evaluation of proportionality (or excessive harm to civilians compared to military advantage) requires balancing two very different sets of values and objectives, in a framework in which all choices will affect human life. States have duties to protect the lives of their civilians and soldiers by pursuing proper military objectives, but they must balance this against their duty to minimise incidental loss of civilian lives and civilian property during military operations. That balancing is inherently difficult, and raises significant moral and ethical issues.3” For the purposes of this blog, the challenge at hand is to clarify the significant moral and ethical issues mentioned.

An influential thought comes from Michael Walzer’s Just and unjust wars. He relates the concept of collateral damage to that of the doctrine of double effect.4 The doctrine tries, with moderate precision, to reconcile the deontological, absolute prohibition on attacking innocent civilians with the utilitarian concept of the necessity to defeat the military capabilities of the enemy – effectively, to reconcile the ‘good’ of defeating an evil enemy, with the ‘bad’ of inadvertently killing innocent civilians

The deontological and utilitarian perspectives can be recognised in Article 51 AP I: while § 1 offers a statement of universalist deontological principle concerning the protection of civilians “in all circumstances”, § 5 sub b offers the utilitarian consideration of military necessity. Noteworthy though frequently overlooked is the fact that the version of utilitarianism used is the non-universalist version: the realisation of the ‘greater good’ refers to the greater good of a specific people or nation, etc, but not the greater good of humankind as a whole. The non-universal, utilitarian concept of military necessity refers to the need to defeat the enemy. Hence, what is ‘the greater good’ for one of the warring parties is virtually by definition detrimental to the other. (Incidentally, the universalist version of utilitarianism is likely to be preferred by humanitarian organisations, which tend to emphasise the universal nature of humanitarianism).

Difference of opinion exists on the question how to reconcile the universalist deontological perspective which informs § 1 with the non-universal utilitarian perspective enshrined in § 5 sub b. The majority opinion seems to be, certainly in the previous century, that utilitarianism should prevail.

The advantage of the utilitarian perspective is that it offers the on-scene commander the flexibility to take into account the vicissitudes on the battlefield: if the situation changes, then his assessment of proportionality can change in equal measure. The disadvantage is that this flexibility is a double-edged sword: if proportionality becomes so utterly dependent on local circumstance, then it is incapable of offering legal protection to the victims of war. A proper protection of the victims of war needs a clear line in the sand: this is still permissible, that no longer is. Thousands of victims of armed conflict, certainly in urban areas, ranging from Vukovar, via Sana’a to Mariupol and Gaza are paying the price for the ambiguity of this double-edged sword.

There is a minority view on proportionality. In its Commentary to Article 51, the ICRC wrote:

“The idea has also been put forward that even if they are very high, civilian losses and damages may be justified if the military advantage at stake is of great importance. This idea is contrary to the fundamental rules of the Protocol (…).

The Protocol does not provide any justification for attacks which cause extensive civilian losses and damages. Incidental losses and damages should never be extensive.”5

The ICRC’s last sentence seems to allude to a complex editorial issue, namely that article 51 uses both the words “incidental” and “extensive”, even though these two words seem to stand in opposition to each other. The minority view appears to be quietly gaining ground. In the Galić case, the International Criminal Tribunal for the former Yugoslavia quoted the ICRC’s perspective approvingly.6 The reader will notice that the point of departure in the ICRC’s perspective is not the non-universal utilitarian concept of military advantage, but rather the universal deontological concept of protection of the victims of war. With its emphasis on deontology, it leaves the impression that the minority interpretation is only to a limited extent dependent on local circumstance – not to the extent as the majority opinion might seem to prefer. Explicit was ICTY in the Kuprešckić case, when it wrote:

“The absolute nature of most obligations imposed by rules of international humanitarian law reflects the progressive trend towards the so-called “humanisation” of international legal obligations (…)

This trend marks the translation into legal norms of the “categorical imperative” formulated by Kant in the field of morals: one ought to fulfil an obligation regardless of whether others comply with it or disregard it.”7

The disagreement between the adherents of the majority and minority views is no academic detail. If one prefers the majority view, then the conclusion is that the IDF is, in most instances at least, doing the right thing in Gaza. While the number of civilian casualties is horrific, Israel can and does argue that it has a case of military necessity8 – a necessity which is not only underlined by the particularly cruel nature of Hamas’ attack of October 7th and its use of indiscriminate missiles at urban areas, but also by the fact that Hamas has repeatedly though illegally used the tactic of human shields. On the other hand, if one prefers the minority view, then the conclusion is inescapable that the IDF has committed very many and very serious war crimes in Gaza. After all, thirty thousand plus civilian casualties in Gaza cannot, by any standard, be described as “incidental”. This argument can also be underlined by additional points, ranging from inflammatory statements of Israel’s political leadership,9 via its use of the AI Lavender targeting system10, to the famine which is, according to the International Court of Justice, 11 setting in.

By remaining ambiguous about the protection of the victims of war on such a key issue as proportionality, IHL has been failing those victims for decades across the globe. A key question, given the pending case of South Africa vs Israel before the ICJ, is therefore how the international judiciary might assess an issue which just as much falls in the realm of military ethics as in the laws of war. Where Martti Koskenniemi suggests that, in time of peace at least, the international judiciary serves as the “gentle civiliser of nations”,12 I have personally had reason to conclude that, when it comes to the laws of war, there exists a generally cautious trend in which the international judiciary shifts away from legal positivism – including its utilitarian connotations – towards an approach which takes account of the values behind the wording of the law, such as the reference to the categorical imperative of Immanuel Kant.13 Recently, in its Order concerning Preliminary Measures, South Africa vs. Israel of January 26th, 2024, the ICJ reiterated the “purely humanitarian and civilizing purpose” of the Genocide Convention and the need to “endorse the most elementary principles of morality”.14

International humanitarian law has failed the victims of war for too long. The nature of circumstances such as the dense population of Gaza, in combination with aerial and artillery attacks frequently carried out at night when most family members are at home, and the type of heavy munitions used, make it possible to conclude that a reasonable commander must have been aware that such attacks could likely result in a high number of civilian casualties as well as in considerable destruction; in other words, that such attacks are likely to be disproportional.15 Thirty thousand plus Gazan civilian deaths cannot be set aside as “tragic” though “unintentional” and therefore permissible. In a conflict where the enemy has been described as “human animals”16 this amounts to a cynical acceptance of a massive loss of life at the cost of the most basic considerations of humanity. This flies in the face of the fundamental aim of humanitarian law as such, which is to protect the victims of war by setting limits on the permissibility of military operations. The international judiciary, be it the International Court of Justice or the International Criminal Court, should not fail the victims again.

The definition of proportionality contains the element of “incidental” civilian losses. This element should be prioritised over another element, which is the relation between the value of the military target and the permissible level of collateral damage. Certainly in urban warfare, military targets can frequently not be isolated from civilians with sufficient precision – this remains true even if one sets aside the tactic of human shields for a moment. It is this vagueness in the law which leads to the insufficient protection of civilians. When the courts prioritise the element “incidental” over other elements of the definition, then the IDF can, and should, be condemned for its disproportional actions in Gaza.


About the author

Dr. Ted van Baarda is a member of the Founding Board of EuroISME. Before being appointed Executive Director in 2015, he taught military ethics at the Netherlands Defence College, and he was a guest lecturer at the Rwanda Military Academy.



1 ICRC, Database on customary IHL, Rule 14.

2 Ministry of Foreign Affairs of Israel, Gaza Operation (also known as Operation Cast Lead), 2009, quoted by the ICRC in its customary IHL database, § 120;

3 Ibid, § 122 (italics added).

4 Michael Walzer, Just and unjust wars. A moral argument with historical illustrations, (1977), pp. 152-153.

5 ICRC, Commentary on the Additional Protocols, (1986), § 1980.

6 ICTY, Prosecutor v. Galić, Case No. IT-01-98-29-T, Trial Chamber, Judgement, 5 December 2003, para. 58 (fn 108).

7 ICTY, Kuprešckić case, Trial Chamber, 14 January 2000, § 518.

8 ICJ, South Africa vs. Israel, oral statement of the co-agent of Israel, verbatim record, Case concerning Application of the Convention on the Prevention and Punishment of the Crime of Genocide in the Gaza Strip, hearings held on Friday 12 January 2024.

9 ICJ, South Arica vs. Israel, Case concerning Application of the Convention on the Prevention and Punishment of the Crime of Genocide in the Gaza Strip, (first) Order concerning provisional measures, 26 January 2024, §§ 51 et seq.

10 Yuval Abraham, “‘Lavender’: The AI machine directing Israel’s bombing spree in Gaza”, +972 Magazine, 3 April 2024, ; Jessica Wolfendale, “’Tragic’ but ‘unintentional’: The myth of honest mistakes and the value of civilian lives in Gaza,” ABC Religion and Ethics, 8 April 2024,

11 ICJ, South Africa vs. Israel, Case concerning Application of the Convention on the Prevention and Punishment of the Crime of Genocide in the Gaza Strip, (second) Order concerning provisional measures, 28 March 2024, §§ 18-21 and 45.

12 Martti Koskenniemi, The Gentle Civilizer of Nations (2001).

13 Ted van Baarda, “Quo vadis? Concepts of moral and legal philosophy underpinning the laws of armed conflict,” Journal of the philosophy of international law, (2014), Vol. 5, issue 2; Ted van Baarda, “Moral Ambiguities Underlying the Laws of Armed Conflict: A Perspective From Military Ethics,” Yearbook of International Humanitarian Law, (2008).

14 Supra, n. 9, § 65.

15 Compare: Report of the United Nations Independent Commission of Inquiry on the 2014 Gaza Conflict, UN doc. A/HRC/29/CRP.4 at § 221.

16 Supra n. 9, § 52.

Picture credit: Shubham Sharan on Unsplash

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