In one video, three apartment towers sit side by side until, suddenly, there are two enormous explosions and two of the buildings collapse. The smoke and debris clear to reveal the third somehow still standing, like a remnant tooth. Spared, but for how long? We don’t know if there are casualties, but the scale of destruction is shocking. We are told it is the result of an airstrike.

In another video, troops rush into what we are told is a basement of a children’s hospital. They appear to discover explosives, weapons and a sinister room where hostages have been held, with a chair, a rope and a bundle of nappies: the stuff of horror movies. The children in the wards above have apparently been used as protection from military assault.

Both episodes – one posted on Instagram in Gaza by photographer Motaz Azaiza, the other released by the Israeli military – seem to fall well outside what we might consider ethical behaviour, even in wartime. Wholesale destruction of civilian property, the use of civilians to shield military targets, hostage-taking: all seem impossible to justify. But are they actually war crimes? What rules must Hamas and the Israeli military follow in this conflict? What happens if they break them?

When did warfare first get rules?

We’ve all heard of the Geneva Conventions, which dictate how warfare should be conducted by civilised entities. Yet there were indications in ancient times that humanitarian concerns were considered then too, including in the Mahabharata, the Old Testament, and by Hammurabi, the sixth king of the first dynasty of Babylon.

His Code of Hammurabi, compiled between 1755BC and 1750BC (a hard copy of which is now in the Louvre), made rules on pretty much everything: lawsuits, adultery, receiving stolen goods, the care of date orchards, and what to do with builders who didn’t put up walls properly. There is much putting to death for what we might today consider fairly minor crimes (if you helped put out a house fire but tried to steal something while you were there, they threw you into the very same fire). But Hammurabi also introduces broader principles, particularly “that the strong might not injure the weak” and that we must “protect the widows and orphans” – sentiments that inform international law today.

In the modern era, a significant effort to regulate warfare itself began in 1859, when Genevan businessman Henry Dunant witnessed the aftermath of the battle of Solferino, near Verona in Italy’s north. A milestone in the efforts to nationalise Italy, it was brutal.

“Here is hand-to-hand struggle in all its horror and frightfulness,” Dunant writes. “Austrians and Allies trampling each other under foot, killing one another on piles of bleeding corpses, felling their enemies with their rifle butts, crushing skulls ... No quarter is given; it is a sheer butchery; a struggle between savage beasts, maddened with blood and fury.”

The Geneva Conventions largely concern the treatment of wounded and sick soldiers, prisoners of war, and the protection of civilians during wars.

Appalled, Dunant suggested that combatants should agree to allow trained volunteer relief groups to treat the wounded. This eventually led to the formation of the International Committee of the Red Cross; it also prompted delegates from 16 countries to meet in Geneva to discuss a humanitarian agreement to govern aspects of warfare. In 1864, they adopted the first Geneva Convention “for the Amelioration of the Condition of the Wounded in Armies in the Field”.

Updated in 1906, 1929 and most substantially in 1949, after World War II, the Geneva Conventions largely concern the treatment of wounded and sick soldiers, prisoners of war, and the protection of civilians during wars, including foreign occupation. In 1977, two more protocols were adopted: one extending the rules applicable in international armed conflict, and the second concerning non-international armed conflicts. Among other things, these prohibited collective punishment (such as revenge on a civilian population), torture, hostage-taking, terrorism and “outrages on personal dignity” – in particular humiliating and degrading treatment, rape, enforced prostitution and any form of indecent assault.

These laws are referred to collectively as international humanitarian law. Other treaties have since added to this tapestry of rules, including restrictions on the use of chemical and biological weapons, anti-personnel mines and cluster munitions. In 1998, the Rome Statute established the International Criminal Court (ICC) in The Hague (in the Netherlands) with jurisdiction over certain violations of international humanitarian law as well as genocide, crimes against humanity and the crime of aggression, which attaches individual criminal responsibility to manifest violations of the prohibition of the use of force.

What rules apply to the Israel-Hamas war?

Five main principles apply: distinction, precaution, proportionality, humanity and military necessity. In the current conflict, these apply equally to the Israeli military and Hamas, which is the elected ruling authority in Gaza (elections were last held in 2006) and which is designated a terrorist organisation by several countries, including Australia.

An army or armed group must distinguish between civilians and “civilian objects” and combatants and “military objects” – and only target combatants. This prohibits indiscriminate attacks on populated areas and means soldiers must take care to target only the enemy while sparing civilians, even if this means they face greater risks themselves. A party to an armed conflict must also take “all feasible precautions to protect the civilian population and objects against the effects of attacks”, says Dr Monique Cormier, senior lecturer at Monash University’s faculty of law.

Proportionality prohibits attacks against military objectives that are expected to cause incidental harm to civilians and civilian objects that would be excessive in relation to the concrete and direct military advantage anticipated. Humanity imposes limits on the means and methods of warfare and requires that those who have fallen into enemy hands be treated humanely, while the principle of military necessity permits only the degree and the kind of force required to achieve the legitimate purpose of a conflict.

Hamas has not adhered to the rules of warfare, particularly those governing the indiscriminate killing of civilians as well as the taking of hostages.

Whatever its avowed justifications for its attacks in Israel on October 7,  Hamas has not adhered to the rules of warfare, particularly those governing the indiscriminate killing of civilians and the taking of hostages – crimes under international humanitarian law, according to the United Nations.

“Hamas is clearly not complying with its obligations,” says Ben Saul, Challis chair of international law at the University of Sydney. However, the killing by Hamas of Israel Defence Forces personnel on October 7 was not necessarily a war crime, he notes. “It’s not prohibited under international humanitarian law for a non-state armed group like Hamas to target state military soldiers in armed conflict.”

It has been reported that the families of nine Israeli victims of the October 7 attacks have lodged a complaint with the ICC asking for Hamas leaders to be prosecuted for genocide and war crimes. Their lawyer stated: “The complaint states that the Hamas terrorists do not deny the crimes committed, which they have amply documented and broadcast, and that the … facts cannot therefore be disputed.”

Many complex factors would be weighed up in examining whether or not Israel itself had breached any of its legal obligations. For example: if an airstrike destroys an apartment block within which a lawful military target is located, was the expected harm caused to civilians and civilian objects excessive compared to the anticipated military advantage; and what precautions were taken to prevent civilian harm?

Says Saul: “If you can accomplish the military task with a 100-kilogram bomb instead of a 500-kilogram one, then you shouldn’t use the more extensive weapons if that’s likely to kill more civilians.” Intelligence gathering is essential, too, he says. “You’ve got to take all feasible measures to verify the military target and learn how many civilians are nearby. They could be using electronic means or drones or informants or visual confirmation – a robust information-collection process, so that you’re not targeting when you don’t know what are going to be the consequences.”

Atrocities committed by Hamas, and the claimed use of civilians as shields, do not excuse Israel from its obligations to target only the military and avoid disproportionate or indiscriminate attacks, says Saul. “It absolutely makes it much harder for Israel to fight. It has to be more discriminating in the way it fights. These are obligations every party owes unilaterally. They’re not dependent on reciprocity.”

‘What exactly is the weapon that you’re using to carry out that legitimate military attack? And what could be the consequences arising from it?’

Donald Rothwell, a professor of international law at the Australian National University, puts it this way: “The expectation is that as a state, you comply with international law.” Before any attack, he says, military forces must run the same complicated calculus. “You can’t drop a missile on a residential tower block in the hope that there might be a Hamas fighter there. You need to have appropriate intelligence to confirm that you can legitimately attack that feature. And you then get into the question of the means and methods of warfare. What exactly is the weapon that you’re using to carry out that legitimate military attack? And what could be the consequences arising from it?”

On October 9, in response to the Hamas attacks, Israel closed its crossings into Gaza. Its Defence Minister, Yoav Gallant, declared: “We are putting a complete siege on Gaza … No electricity, no food, no water, no gas – it’s all closed.” Could Israel’s blockade be a breach of humanitarian law, amounting to collective punishment?

Some groups think so. On November 10, three Palestinian human rights organisations asked the ICC to investigate Israel for alleged war crimes committed in the current conflict and called for arrest warrants to be issued against Israel’s President, Isaac Herzog, Prime Minister Benjamin Netanyahu and Gallant.

The brief prepared by human rights organisations Al Haq, Al Mezan and the Palestinian Centre for Human Rights called for “urgent attention” on “the continuous barrage of Israeli airstrikes on densely populated civilian areas within the Gaza Strip”.

The document also asked the court to investigate “the suffocating siege imposed on [Gaza], the forced displacement of its population, the use of toxic gas, and the denial of necessities, such as food, water, fuel and electricity”.

Relevant rules that come into play amid blockades and mass airstrikes, says Cormier, are prohibitions on starving civilian populations as a method of warfare; destroying objects indispensable to the survival of a civilian population; the obligation to facilitate the rapid and unimpeded passage of humanitarian relief for civilians in need; and the need “to ensure that persons deprived of their liberty must be provided with adequate food, water, clothing and medical attention”.

Netanyahu has dismissed accusations that Israel is collectively punishing the more than 2 million Gazans for the crimes of Hamas.

Do hospitals have special protections?

By mid-November, Israeli military forces had encircled Gaza City, flattened multiple buildings in airstrikes, engaged Hamas fighters on the ground and turned their focus to the sprawling Al Shifa Hospital, where they said Hamas was harbouring a command centre.

“International humanitarian law does require the protection of hospitals, of patients and of medical staff,” Australian Foreign Minister Penny Wong said as forces prepared to move on the hospital. She called on Israel “to cease the attacking of hospitals” while acknowledging, “we understand the argument that Hamas is burrowed into civilian infrastructure. But, you know, I think the international community, looking at what is occurring in hospitals, would say to Israel: these are facilities protected under international law and we want you to do so”.

So when Israeli forces finally entered the grounds of Al Shifa, were they breaking the rules of war? Not necessarily, if the assault was justified militarily and the usual rules, including necessity and proportionality, were observed. While a hospital could normally claim protection, says Ben Saul, “it can lose that immunity from attack if it is used for military purposes by one of the parties to the conflict”.

‘You have to weigh up the direct and concrete military advantage ... against the impact of taking out one of the last remaining functioning hospitals in Gaza.’

Also of note, Article 19 of the fourth Geneva Convention states: “The protection to which civilian hospitals are entitled shall not cease unless they are used to commit, outside their humanitarian duties, acts harmful to the enemy. Protection may, however, cease only after due warning has been given, naming, in all appropriate cases, a reasonable time limit and after such warning has remained unheeded.”

Initial reports suggested widespread bloodshed was avoided in the raid itself, although the hospital director, Mohammad Abu Salmiya, told news agency Al Jazeera that soldiers had shattered several windows and wounded people with shrapnel. At the time of writing, Israeli forces were still searching the hospital; they said they had discovered equipment including AK-47s, grenades, military uniforms and a battle vest with the insignia of Hamas’ military wing, as well as a tunnel shaft in the hospital grounds. Hamas said claims that the group uses Al Shifa for military purposes “is a repetition of a blatantly false narrative”.

Prior to the assault, say experts, Israel should not only have considered the risk to civilian lives but also the possible ongoing cost to the civilian population that might result from damage to health facilities. Says Dr Carrie McDougall, international law academic at the University of Melbourne and a former Australian government legal adviser: “You have to weigh up the direct and concrete military advantage of taking out or limiting the capabilities of the Hamas headquarters against the direct impact of civilian harm and the impact of taking out one of the last remaining functioning hospitals in Gaza.”

So, what happens if combatants break the rules?

Not all breaches of the accepted laws of armed conflict constitute war crimes. Cormier defines a war crime as “a particularly egregious violation that occurs during armed conflict” that gives rise to individual criminal liability. “And liability is not limited to lower-level soldiers who carried out the war crime. Commanders and civilian leaders may also be held individually, criminally liable for such crimes.”

Hostage-taking, torture, rape and directly targeting civilians are all cut-and-dried war crimes. The use of human shields can also be considered a war crime: the ICC says it is an offence to use “a civilian or other protected person to render certain points, areas or military forces immune from military operations”.

Nor does it matter if the people being used as shields are aware of it or not, says Cormier. “If the persons being used as human shields are civilian, then they are entitled to all the usual protections and cannot be targeted. If they are shielding a legitimate military objective, then any attack on that objective must be necessary for a concrete and direct military advantage and not result in disproportionate harm to those or any other civilians.”

‘You had a mass-atrocity crime occurring within Israel. So if you wanted to, you could, in Israel, resort to the use of Israeli criminal law ...’

How to punish perpetrators? On one “very basic” level, says ANU’s Donald Rothwell, the October 7 assaults by Hamas were a mass violation of Israeli criminal law. “You had a mass-atrocity crime occurring within Israel. So if you wanted to, you could, in Israel, resort to the use of Israeli criminal law to bring about the prosecution of the perpetrators of those crimes in multiple different ways.”

More broadly, however, those crimes and any others committed during this conflict could be examined by the ICC, which carries out its investigative work through the Office of the Prosecutor, led since 2021 by British lawyer Karim Khan.

In October, Khan clarified: “If there is evidence that Palestinians, whether they’re Hamas or al-Quds Brigades or the armed wing of Hamas or any other person or any other national of any other state party, has committed crimes, yes, we have jurisdiction wherever they’re committed, including on the territory of Israel.” He later added: “Israel has clear obligations in relation to its war with Hamas: not just moral obligations, but legal obligations that it has to comply with the laws of armed conflict. It’s there in the Rome Statute. It’s there in black and white. It’s there in the Geneva Conventions. It’s there in black and white.”

However, for any prosecution to take place, accused individuals would either need to voluntarily give themselves up to the court – which would be unlikely – or find themselves in one of the 123 member states, which would be obliged to detain and surrender them. Russian President Vladimir Putin is now in this position, with a warrant issued for his arrest for the war crime of deporting Ukrainian children to Russia during the conflict that is still raging in Ukraine.

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