The precarious rules of war

The erosion of a crucial distinction

Western governments are quick to call out Russia for committing war crimes when it causes civilian casualties in Ukraine, while exculpating Israel when it does the same in Gaza. But focusing only on whether the war itself in each case is legal, while ignoring the way the warfare is conducted, erodes a crucial distinction in international law, argues Hew Strachan.   


Russia’s war in Ukraine, and now Israel’s war against Hamas in Gaza, have intensified the already heated debate around the international law governing war. But the ways in which these laws are being cited threaten to distort the crucial distinction between ius ad bellum (the law governing the resort to war) and ius in bello (the law affecting war’s conduct).  Because Russia’s war is illegal, some presume that the way in which its armed forces fight is also illegal.  That may well be proved by due process, but legally fighting an illegal war doesn’t necessarily imply that the war is being fought in an illegal manner.

On the other front, the Hamas attack on Israel clearly breached both forms of law: it was an act of aggression and it deliberately killed non-combatants with extraordinary and provocative brutality. By rising to the provocation, Israel is relying on the legality of its decision to go to war to justify how it is now fighting that war. But the the right to respond to attack does not legitimise illegal ways of fighting. The charge that it is killing innocent civilians in Gaza, if proven, will be a breach of ius in bello.  Western powers, like the United States, Germany and the United Kingdom, who have supported Ukraine and now back Israel, are caught between a rock and a hard place. In Israel’s case they say that some civilian casualties in war are inevitable, especially in densely populated areas, but this is not a mitigation that they have  so far allowed to Russia’s armed forces – not least because its resort to war was unjust. If international law is not applied equally to all countries engaged in warfare, whether enemies or allies, it loses its claim to impartiality.


Since 2009 both the United States and the United Kingdom have increasingly rationalised their foreign and security policies as a defence of ‘the rules-based international order’, not as support for international law.


Since the 9/11 attacks in 2001, international law has exercised a growing influence on the political and strategic aspects of war’s conduct. For some powers at least, international humanitarian law shapes how they use armed force and how they make the case for its employment to international opinion. In the Second World War, warcrimes only reached the courts after the fighting was over.  Seen by some as victors’ justice, they focused on senior leaders accused of waging aggressive war in contravention of the 1928 Kellogg-Briand pact rather than on junior figures accused of war crimes committed in the course of the war.  Today detailed evidence of war crimes is being collected while the conflict is ongoing and before the war’s outcome is known. Germany, for example, is proposing to prosecute senior Russian officers for crimes against humanity under the principle of ‘universal jurisdiction’.

The Russian invasion of Ukraine breached not just the Kellogg-Briand pact but also the United Nations Charter, which prohibits the use of war except in self-defence. But the illegitimacy of a state’s resort to war does not deprive those who fight on its behalf of belligerent rights -  that is, of the legal rights and protections they enjoy as recognised and identifiable combatants'.. They must be treated as prisoners of war if they surrender and be returned home when the war is over.  Of course, they also have obligations – especially that which requires them to distinguish between combatants and non-combatants. The presumption underpinning international humanitarian law is that war will be used with discrimination and discipline. But the way in which the war is being discussed suggests that the distinctions are too fine for both traditional and online social media.

For example, on 29 July 2022, Sergeant Vadim Shishimarin of the Russian army was convicted of murdering Oleksandar Shelipov on 28 February in Chupahivka in north-eastern Ukraine. The Russians feared that civilians might report their position and his superior officer ordered Shisihimarin to kill Shelipov, who was talking on his mobile phone while riding a bicycle.  Shishimarin agreed at his trial that he was not required to follow an illegal order and so had committed a war crime.  His unit had come under Ukrainian attack earlier in the day and was in a combat zone. In past wars, deaths such as Shelipov’s would have been deemed the unavoidable collateral damage of war, or the product of ‘military necessity’.  But none of the reports in the western press suggested such a plea had been entered in Shishimarin’s defence. Think, in contrast, what the public response might be to a Ukrainian attack, say in Crimea or more directly in Russia itself, which resulted in the deaths of Russian civilians. Would such an act be condemned, like that of Shishimarin, or would it be seen as simply the collateral consequence of striking a legitimate target?

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This erosion of the distinction between ius ad bellum and ius in bello has not crept up on us unawares. George W. Bush’s global war on terror did not accord belligerent rights to Al Qaeda and Taliban fighters because they terrorists (a description President Zelensky uses of Russians) - as Abu Ghraib and Guantánamo Bay testified. Nor were they given the right to trial accorded to criminals.  Instead, they were deprived of any legal status. When Obama and Trump shifted the emphasis of intervention from ‘boots on the ground’ to the use of drones in targeted attacks, they executed terrorists without trial – and sometimes pre-emptively. They also applied armed force in sovereign states, including Pakistan and Yemen, with whom the United States was not at war – so breaching ius ad bellum, while simultaneously proving themselves ready to accept collateral damage and the killing of civilians (a breach of ius in bello). The United States justified its actions less through the prism of international law and more through the reinterpretation if US laws.


A rules-based international order, in which the west makes the rules and then decides which it will obey and which not, cannot hold.


In November 2001, the US Air Force Deputy Judge Advocate General, Charles Dunlap, coined the term ‘lawfare’ to describe the exploitation of the laws of war as a weapon of war, but he attributed its use to America’s enemies.  Today, American legal scholars like Orde Kittrie argue that ‘lawfare’ is used by the United States itself (as well as by Israel). When legal arguments have such political and international purchase, the effort to manipulate them according to the desires of the belligerent can undermine international law itself.  The consequence of such practices could be that any power may struggle to justify its use of armed force, even if the resort to war is justified as a response to aggression.

Since 2009 both the United States and the United Kingdom have increasingly rationalised their foreign and security policies as a defence of ‘the rules-based international order’, not as support for international law.  The shift reflects the increasingly weakness of the west's the courts of global opinion when it uses or backs the use of armed force.  In 1990-91 the United States carefully orchestrated its response to Iraq’s invasion of Kuwait with successive United Nations Security Council Resolutions but in 2003 it invaded Iraq without any UNSC resolution. In 2011, Britain, France and the United States exceeded the mandate given them by the United Nations to protect civilians in Benghazi by effecting regime change in Libya. For some, the United States talks the talk but it does not walk the walk. It has not ratified the UN Charter on the Law of the Sea and it is not a state party to the International Criminal Court, the body charged with examining possible war crimes.  A rules-based international order, in which the west makes the rules and then decides which it will obey and which not, cannot hold.  Although a solid majority of the world’s states have endorsed successive motions in the United Nations General Assembly condemning Russia’s invasion of Ukraine, a stubborn minority have abstained or supported Russia.  As they include both China and India, they speak for half the world’s population.

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The distinction between ius ad bellum and ius in bello may be irrecoverable, however powerful the protestations of international lawyers.  The separation they make between a state (as the party that goes to war) and the individual (as the person who does the fighting) is at odds with the democratic idea that citizens have political agency. A recent report - that some Ukrainian and western officials want to treat all Russian combatants, even if they have deserted and fled Russia, as responsible for Russia’s war - makes that point.  So does the determination of many Israelis to hold all Palestinians accountable for the atrocities committed by Hamas. But if, in the midst of such violence, we want to enforce the rules that govern war, we need to use the vocabulary of international law, which has global legitimacy, not that of an international order regulated and defined by one dominant power.

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