In Honor of Yoram Dinstein – Will the Separation Between Jus ad Bellum and Jus in Bello Survive the Conflicts in Ukraine and Gaza?

Editors’ note: This post is part of a series to honor Professor Yoram Dinstein, who passed away on Saturday February 10, 2024. These posts recognize Professor Dinstein’s work and the significant contribution his scholarship has made to our understanding of international law.

One of the qualities that makes Yoram Dinstein such a unique scholar is that he is one of the very few genuine experts in both jus ad bellum (the rules on the legality of the use of force) and jus in bello (the rules on how force may be used, which comprise International Humanitarian Law (IHL)). He has never mixed the two branches or nuanced the absolute separation between them. On the contrary, he has insisted on strict separation in many of his writings.

The foregoing passage is originally from a 2007 essay honoring Yoram Dinstein, titled “Ius ad bellum and Ius in Bello – The Separation between the Legality of the Use of Force and Humanitarian Rules to be Respected in Warfare: Crucial or Outdated?” In my essay, I explored this separation—in my view, crucial for the survival of IHL and for the effective protection of war victims—as well as its reasons and consequences, the threats it faces, and tendencies at the time that could have made such separation pointless. In the meantime, it has from time to time again been suggested that the total separation is “oversimplified” (see here).

However, the separation of jus ad bellum and jus in bello is essential to the effectiveness of IHL in all armed conflicts, since most of those who fight are indeed convinced —and all of them claim—that their cause is just and that of their adversary unjust. If the rules governing the conduct of those fighting to defend their country against aggression were relaxed, the parties would never be able to agree, in the course of an armed conflict (when IHL is supposed to exert its protective effect), on who should abide by which rules. The humanitarian reasons for this equality of the belligerents before IHL are even more compelling. People affected by armed conflict need as much protection against a belligerent who fights in accordance with jus ad bellum as against a belligerent who violates it. That “their” State has violated the jus ad bellum is not their fault.

However, the two current armed conflicts in Ukraine and Gaza that monopolize the attention of public opinion and scholars—at least in Europe, North America, and the Near East—have shown once again how difficult it is for the public and governments to accept this separation, not only in the countries directly affected. In addition, the law of naval warfare (also combined with the law of neutrality) always consisted of both jus ad bellum and jus in bello rules, difficult to delineate. When force may be used on land against a neutral State is clearly a jus ad bellum question, while it is the law of naval warfare that determines when a neutral ship may be attacked. The conflict in Ukraine has raised legitimate questions whether both the aggressor and the State fighting in self-defence have the same “rights” towards enemy and neutral merchant ships as the separation between jus ad bellum and jus in bello seems to require.

Ukraine

Due to the Russian aggression against Ukraine, all those who analyse the observance of IHL in the resulting international armed conflict are confronted with, or even succumb to, the constant amalgam—understandable, but legally erroneous—between jus ad bellum and jus in bello. Although Ukraine is the victim of an armed attack by Russia, and is merely defending itself, both Russia and Ukraine must abide by the same rules of IHL. However, legally correct statements in IHL, such as that if Ukraine defends every house in a village, Russian armed forces may, without violating IHL, attack every house, shock Ukrainian interlocutors and Ukrainian and international public opinion.

One of the consequences of this rejection of the distinction between jus ad bellum and jus in bello is indifference to the admittedly less systematic violations committed by Ukraine. In particular, Western governments and public opinion show little concern for the treatment of Russian prisoners of war (POWs), which raises serious concerns (paras. 88-124). It is astonishing that a country like Ukraine, which claims to defend Western values, still does not give the International Committee of the Red Cross (ICRC) access to all its POWs, in clear violation of IHL (Geneva Convention (GC) III, art. 126(4)). We can only hope that the Western countries that support Ukraine will remind it of this, as they must do according to Article 1 common to the Geneva Conventions (see also Zwanenburg).

Gaza

When it comes to the conflict in Gaza, it is much more controversial who violates the jus ad bellum. Based upon State practice since 2001, Israel has a good claim to exercise its right to self-defence against a non-State actor like Hamas, although this is contested by some. One may nevertheless doubt whether the support to this claim in the Western world would have been the same if Hamas had killed 1,200 Israeli soldiers in an attack compliant with IHL instead of committing the October 7, 2023, massacre.

As for the Palestinian people, it has a right to self-determination and may exercise it according to UN General Assembly resolutions (see, for example UN General Assembly Resolution 2105 (XX) 1965) using force. Admittedly, such force may only be used by the national liberation movement and not by Hamas. However, the Palestinian Liberation Organization has, to my knowledge, never disavowed the use of force by Hamas. The fact that so many Palestinians and their supporters in the Arab World and Western countries remain silent on the horrible IHL violations committed on October 7, 2023, can only be explained by the fact that they consider the Palestinian cause just and therefore mix up jus ad bellum and jus in bello.

The good news is, nevertheless, that research into statements by officials, scholars, non-governmental organizations and UN mandate holders supporting either Israel or the Palestinian cause found only a retired Kenyan politician who wrote, after explaining the legality of the Palestinian struggle, “Consequently, all actions by Hamas or any other Palestinian armed resistance groups are lawful and do not constitute terrorism.”

Neutrality and Impartial Humanitarian Action

For reasons similar to those which make it difficult to accept the equal applicability of IHL to both sides, Ukraine, Western public opinion, Israel and many Palestinians and their supporters have had, and continue to have, great difficulty in accepting the neutrality of the ICRC’s humanitarian action in those conflicts. Yet this neutrality is essential for the ICRC gaining access to all the victims of the conflict.

For example, the former ICRC President was strongly criticized for meeting Russian Foreign Minister Sergei Lavrov (see also reactions of the former ICRC President to that criticism here and here). Ukraine protested against the ICRC’s willingness to assist Ukrainians in southern Russia, who Russia claimed were refugees, while Ukraine argued that they had been deported to Russia in violation of IHL. On social networks, the ICRC was criticized for becoming an accomplice to this war crime. Finally, Ukraine has lashed out at the ICRC for not publicly criticizing Russia’s violations of IHL, and for not doing enough to gain access to Ukrainian POWs interned in Russia. As for Israel, it criticizes the ICRC for not doing enough to get access to the Israeli hostages.

NGOs Criticizing Those Engaged in Self-Defence

Even NGOs committed to protecting human rights have had to suffer the consequences of this situation. Amnesty International, for example, issued a statement criticizing Ukraine for deploying its soldiers among concentrations of civilians, putting them at risk of Russian attacks. It immediately came under a storm of criticism (see, for example, Max Boot, Michael Schmitt, Julia Grignon) from Ukraine and Western public opinion, as well as from its own activists and some IHL experts.

In my opinion, this criticism was not so much due to Amnesty’s insufficient analysis of the practical feasibility of deploying its troops in alternative positions, but to the feeling that it was unacceptable to criticize Ukraine when it was defending itself against Russian invasion. Facing this storm of criticism, Amnesty International asked a panel of IHL experts to review its statement from an IHL point of view. In its report, that panel expressed some reservations about Amnesty’s interpretation and application of the IHL rules on passive precautions to be taken by the defender, but fully endorsed the legitimacy for a human rights organization to criticize violations of IHL by a State that is a victim of aggression.

The aforementioned case also demonstrated the importance—and difficulty in public perception—of keeping separate the concepts of attacker and defender in the IHL sense (Additional Protocol (AP) I, art. 49(1)) and those of aggressor and State fighting in self-defence. In 2022, Ukrainian forces were not only “defenders” in the sense of implementing Ukraine’s right to self-defence against an armed attack under the UN Charter. They were also “defenders” in the sense of IHL, in that they and the civilian population under their control were subject to offensive acts of violence by Russia. Those two meanings of “defender” do not always coincide. In the summer of 2023, Ukrainian forces were still fighting in self-defence in the sense of the jus ad bellum but when they successfully liberated some territory Russia had occupied, they turned into attackers and Russian forces became defenders in the sense of IHL.

The Law of Naval Warfare in Ukraine

One particular aspect of IHL which has raised understandable controversy in relation to the armed conflict in Ukraine is the application of the law of naval warfare. With much more force than for the rest of the laws of armed conflict, it has been argued (p. 324–90) even before 2022 that the UN Charter has rendered many rules of the law of naval warfare, which give belligerents “rights,” obsolete.

Whether IHL provides some authorizations or only foresees prohibitions and prescriptions is a controversial issue. In any case, because of the separation between the jus ad bellum and jus in bello, such authorizations could not justify conduct of the aggressor under the jus ad bellum. Even killing soldiers on the battlefield may constitute an act of aggression. Similarly, even those who claim that soldiers have a “right” to kill or capture enemies do not claim that those enemies may not resist being captured or killed, even though this would be the logical consequence of the exercise of a right. When it comes to the law of naval warfare, however, all this is much less clear.

The traditional law of naval warfare clearly gave belligerents in international armed conflicts some authorizations to search and visit merchant, i.e. civilian, ships (San Remo Manual on International Law Applicable to Armed Conflicts at Sea (SRM), paras. 114, 118). What is more, this “right” did not only cover enemy but also neutral ships (SRM, para. 114). Under certain circumstances, all those ships (and/or their cargo) could be confiscated as prize (SRM, para. 146) and even be attacked (SRM, para. 151), including when they were not military objectives. Finally, and most outrageously, a blockade against enemy ports could be enforced, on the high seas, including against neutral ships.

The argument that an aggressor State cannot enjoy such “rights” after having violated the prohibition on the use of force enshrined in the UN Charter may therefore be well-founded in law and is even convincing to me, although I am greatly attached to the absolute separation between jus ad bellum and jus in bello. The international reaction to acts of naval warfare by Russia, which could be lawful under the traditional law of naval warfare, reinforces this tendency. Otherwise, it would be impossible to explain why the United States strongly condemned the stop and search of contraband on a Turkish ship in the Black Sea, although the conduct of the Russian sailors exactly applied, according to two U.S. military lawyers, what the U.S. Department of Defense Law of War Manual prescribes in such a situation. The UK Manual on the Law of Armed Conflict (§ 13.3) at least admits that jus ad bellum limitations apply in addition to the rules of the traditional law of naval warfare. I would, however, not go as far as considering that even the right to take enemy State property as war booty is outdated (p. 333–36), which would mean that a belligerent violates IHL if it confiscates an enemy warship to use it.

What is more astonishing from the jus ad bellum starting point is that an author who argues that the jus ad bellum thus prevails even considers (p. 329, 374–75) that such “rights” are today equally abolished for the State fighting in self-defence (or with UN Security Council authorization). The justification that such “rights” no longer exist even for a State fighting in conformity with the UN Charter is based on the arguments usually made to explain the equality of belligerents before IHL, in particular the fact that it is nearly always controversial who is right under the jus ad bellum. Nevertheless, there is no such thing as equality of belligerents before the jus ad bellum and at least the “rights” concerning neutral ships belong in my view to this body of law. I would argue that self-defence may also be a circumstance precluding the unlawfulness of measures violating rules protecting neutral ships, as long as the jus in bello rules of the law of naval warfare are respected. Admittedly, this reintroduces through the backdoor the problem that who violated the jus ad bellum is nearly always controversial and that international adjudication intervenes at best when the conflict is over, while IHL must be implemented during the conflict.

There are therefore powerful reasons for considering that many rules of the law of naval warfare, which differ from the rules of land warfare, can no longer be invoked by an aggressor.

Conclusion

The strict separation between jus ad bellum and jus in bello and the resulting equality of belligerents before IHL is and has always been difficult to accept for those who fight for a just cause, claim to fight for a just cause or support them. It is, however, inherent in the idea that war, unlike crime, is not only prohibited but also regulated by rules on how to conduct it. This may even be one of the essential features of war.

We may still hope that one day strengthened international institutions will be able and willing to enforce the rule of international law, including the prohibition on the use of force. In such an environment there could be no more equality before the law between those who enforce international law and those against whom it is enforced. Unfortunately, contemporary reality is still very far away from the utopia just described. The world is still made up of sovereign States. Even when they violate international law, they cannot yet be perceived as simple criminal gangs, made up of criminal individuals.

In addition, despite all progress made by international criminal law and international criminal justice in recent years, the possibility to hold accountable those very individuals who decided the course of action resulting in a violation of international law by their State is still underdeveloped and depends very much on the goodwill of States to co-operate. This implies that conduct contrary to the common interest and law and order in the international community must also still be attributed to States, with the necessarily collective reaction resulting from such attribution.

Finally, in the absence of an efficient international system of adjudication, there may, in a given armed conflict, still be bona fide divergences of view on which side is the outlaw and which side is fighting for the common interest.

As long as these realities remain unchanged, the law trying to protect those involved in and affected by a social phenomenon—war by opposition to crime—should not disappear before the phenomenon to which it applies itself disappears. This law is IHL, including the separation which must be drawn between it and the legitimacy of the cause of the parties involved. This does not preclude us from enquiring whether some rules, such as those on belligerent “rights” towards neutrals in naval warfare, really belong to IHL or are not rather part of the jus ad bellum, which, by definition, does not treat the aggressor and the State fighting in self-defence equally.

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Marco Sassòli is Professor of International Law at the University of Geneva Faculty of Law.

Photo credit: IDF Spokesperson Unit