Israel maintains that its use of force is a justified response to acts of terrorism. It considers itself to be in a just war with Hamas and asserts its inherent right of self-defence. The violence against and taking hostage of Israeli civilians on 7 October 2024 are crimes against humanity prohibited in international law. Many in the international community allege that Israel in response is acting disproportionately against the civilians of Gaza and is itself guilty of war crimes, crimes against humanity and genocide.

War is not wholly illegal in international law. However, at the end of World War 2 the judges of the International Military Tribunal (IMT) at Nuremberg declared waging aggressive war an international crime on the part of the aggressor State as well as any individual acting for it.

The prohibition found expression in Article 2(4) of the UN Charter which outlaws acts of armed aggression by one State against another. The proscription is qualified by the exception in Article 51 which provides that nothing in the UN Charter shall impair a State’s inherent right of self-defence against an armed attack. It is upon this provision, or its spirit, which Israel relies, in part, to justify its operation against Hamas.

Strictly speaking, the Israel-Hamas conflict does not constitute a war in international law. The armed conflict in Gaza is better characterised as an insurgency or rebellion. International law regards internal insurrection as a matter within the purview of domestic law.

Complicated

But the legal situation is complicated by the acceptance of the right to self-determination. All States are under a duty to refrain from any forcible action which deprives people of their right to self-determination; and resistance to such forcible action will not violate international law.

The International Court of Justice (ICJ) held in the Western Sahara case (1975) that there is now a rule of customary international law rendering colonial domination by military power unlawful.

In keeping with this line of thought, in 2004, the ICJ affirmed the principle of self-determination of the Palestinian people and held that Israel is an “occupying power” in Palestine. Any threat against Israel arising from the occupation originates within and not outside Palestine. Accordingly, as forceful opposition to the occupation is not imputable to a foreign State, Israel cannot invoke the right of self-defence under Article 51; which correspondingly does not govern the use of force by Hamas in “self-defence” against the occupation.

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Nevertheless, Article 1(4) of Protocol I to the Geneva Conventions adopted in 1977 equates armed conflicts “in which peoples are fighting against colonial domination” with international armed conflict.

Thus, when force is used by a State to suppress the right to self-determination, countervailing force is considered legitimate under international law, provided there is compliance with the law of armed conflict (the prohibitions against war crimes, crimes against humanity and genocide) applicable to States and non-State belligerents alike. Observance of the norms of international humanitarian law are mandatory.

Normally, reciprocity and State consent are the foundations of international customary law and treaty law, but since World War 2 international law has developed the concept of ius cogens as an exception to the principle of consent. International law now recognises a limited number of peremptory norms from which no derogation is permitted.

Prohibitions on State aggression, genocide, slavery, apartheid, and gross violations of human rights are now all ius cogens. Thus, from a legal perspective, little turns practically on Israel’s unsustainable invocation of self-defence. Genocide and crimes against humanity in the conduct of armed conflict cannot be justified under any circumstances, including purported self-defence.

Humanitarian code

The Armenian genocide between 1915 and 1923, the Holocaust and the Nuremberg trials added impetus to the development of a humanitarian code aimed at making armed conflict less inhumane. A coherent body of international humanitarian law and effective mechanisms to enforce it have since emerged in a multitude of international instruments including the Genocide Convention of 1948, and the Geneva Conventions of 1949.

Although none of the Nazi accused at Nuremberg was convicted of genocide, the Genocide Convention owes its provenance to debates about the scope of the criminal charges and the perspectives of two eminent international lawyers involved in the trials, Hersch Lauterpacht and Rafael Lemkin, Jewish refugees from the Holocaust, who never met, but by remarkable coincidence were both born in the city of Lviv (then Lwow) in Ukraine.

Lemkin is credited with coining the term “genocide”. He saw it essentially as the denial of the right of a people to exist through a composite of different acts of persecution or destruction ranging from physical elimination to the “forced disintegration” of a people’s political and social institutions, culture, language, national sentiments and religion.

Lemkin argued passionately for including genocide in the charges with the aim of protecting groups from destruction as in the Jewish experience of the Holocaust. Lauterpacht, on the other hand, was sceptical about the new term and its practical utility. He was concerned that the protection of groups would undermine the protection of individuals and thus should not be the primary focus. He argued that the concept of crimes against humanity would suffice to do justice.

In the end, Article 6 of the Charter of the IMT did not include the crime of genocide and restricted the jurisdiction of the IMT to three categories of crimes: crimes against peace (State aggression); war crimes (violations of the laws of war including inhumane treatment of civilians and prisoners of war, hostages and the wanton destruction of cities not justified by military necessity); and crimes against humanity (inhumane acts committed against any civilian population before or during the war, or persecutions on political, racial or religious grounds whether or not in violation of the domestic law of the country where it was perpetrated).

War crimes and crimes against humanity

The essential difference between war crimes and crimes against humanity is that war crimes are committed in times of war against nationals of another State, while the latter are acts committed against nationals (German Jews) of the same State as the perpetrators (Germany) in times of war or peace (non-war). The Holocaust no doubt was a crime against humanity as well as genocide.

Though genocide was included in some of the charges against the Nazi perpetrators and was raised in both cross examination and argument during the Nuremberg trials, the IMT, much to the disappointment of Lemkin, made no findings in relation to genocide in its judgment. Crimes against humanity, however, were central in the judgment and, for the first time in history, such crimes were recognised to be an established part of international law.

Lemkin was vindicated not long after the Nuremberg trials with the adoption of the Genocide Convention in 1948 declaring genocide a crime under international law. The adoption of the Genocide Convention was seen as fitting international recognition of the need to “liberate mankind from… the odious scourge” inflicted upon the Jewish people during the Holocaust and World War 2.

Genocide is defined as: i) the intentional killing of or causing of serious bodily or mental harm to members of a national, ethnical, racial or religious group; ii) the deliberate infliction on the group of conditions of life calculated to bring about its physical destruction; iii) the imposition of measures intended to prevent births within the group; and iv) the forcible transfer of children of the group to another group.

The perpetrators’ specific intent to destroy the group in whole or in part distinguishes genocidal acts from other international crimes.

Importantly, Article IX of the Genocide Convention confers jurisdiction on the ICJ to determine disputes between States relating to the interpretation, application or fulfilment of the Convention, including those relating to the responsibility of a State for genocide. Both States and individuals can be held criminally responsible for genocide. Individual criminal liability arises from committing, attempting, conspiring and aiding and abetting (complicity in) genocidal acts. State responsibility will arise when an individual has committed genocide exercising State authority and the individual’s conduct is attributable to the State.

The essence of the Geneva Conventions is the principle that persons not actively engaged in warfare should be treated humanely. The only legitimate object which States should endeavour to accomplish during a war is to weaken the military forces of the enemy and thus a distinction must at all times be drawn between civilians and combatants. Belligerent attacks must be strictly limited to objects which contribute to military action or offer a definite military advantage.

International Criminal Court

The events in the former Yugoslavia and Rwanda at the end of the last century led to the creation in 2002 of the International Criminal Court (ICC) with jurisdiction over genocide, crimes against humanity and war crimes committed in the territory of a State party to the Rome Statute. The jurisdiction is limited to individuals and not States and proceeds on the basis of the principle of complementarity, meaning that it only intervenes when national authorities are unwilling or unable to prosecute crimes within their own jurisdiction.

Israel is not a party to the Rome Statute. However, in February 2021 the ICC held that as Palestine is a party to the Rome Statute, the ICC has jurisdiction in relation to the situation in Palestine. Thereafter, on 23 March 2021, the ICC Prosecutor announced the opening of an investigation into various complaints filed against Israel since 2015.

After the commencement of Israel’s action in Gaza in October 2023, South Africa took two significant actions on the international stage.

First, on 17 November 2023, it made a referral to the ICC requesting it to investigate whether in the context of the situation in Palestine specific individuals should be charged with genocide, crimes against humanity and war crimes in relation to conduct after 7 October 2023. This investigation is ongoing.

Six weeks later, on 28 December 2023, South Africa took the unprecedented step of referring a case of genocide against Israel to the ICJ in terms of Article IX of the Genocide Convention seeking orders inter alia: i) declaring Israel in breach of the Genocide Convention; ii) directing Israel to cease killing or causing serious bodily or mental harm to Palestinians and deliberately inflicting conditions of life calculated to bring about the destruction in whole or in part of the Palestinian group; and iii) granting measures to ensure that persons committing genocide are punished by a competent national or international tribunal.

The application to the ICJ included a request for the indication of provisional measures, including that Israel immediately suspend its military operations and desist in killing, causing harm and inflicting conditions of life calculated to bring about the physical destruction of the Palestinian group in whole or in part.

The ICJ has power to indicate provisional measures under Article 41 of the ICJ Statute when there is a real and imminent risk that irreparable prejudice may be caused to the rights which are the subject of the pending ICJ proceedings. The ICJ may exercise this power only if it is satisfied that the rights asserted are at least “plausible”. The standard of plausibility is less than the ordinary evidentiary standards applicable in civil and criminal cases, respectively, the balance of probabilities or beyond reasonable doubt.

Evidence before the ICJ, reflected also in the report of the Special Rapporteur (SR) on the human rights situation in Palestine released on 25 March 2024, supports a plausible case of genocide.

Thousands of civilians in Gaza have been killed by bombing, sniper fire or in summary executions, some while fleeing to areas declared safe by Israel. Many more lie unaccounted for under the rubble of bombed infrastructure and residential buildings.

Israel has employed over 25,000 tons of explosives (equivalent to two nuclear bombs) on innumerable buildings and used unguided munitions (dumb bombs) and 2,000-pound “bunker buster” bombs on densely populated areas and safe zones. Seventy percent of recorded deaths have consistently been women and children.

Most life-sustaining infrastructure has been destroyed or severely damaged, including 77% of healthcare facilities, 68% of telecommunication infrastructure, large numbers of municipal services, commercial and industrial sites, almost half of all roads, over 60% of Gaza’s 439,000 homes, 60% of residential buildings, all universities, 60% of other educational facilities, including 13 libraries.

Israel has also destroyed at least 195 heritage sites, 208 mosques, three churches and the Gaza Central Archives thereby erasing 150 years of history. Fifteen percent of the women giving birth in Gaza are likely to experience complications, and thus maternal and newborn death rates are expected to increase due to the lack of access to medical care. Ninety-three percent of the population in Gaza is facing crisis levels of hunger, with insufficient food and high levels of malnutrition, possibly escalating to a full-scale famine. By the end of January 2024, over one million civilians were forcibly displaced southward.

On 26 January 2024, taking account of the “catastrophic humanitarian situation” in Gaza, together with “discernibly genocidal and dehumanising rhetoric coming from senior Israeli government officials”, the ICJ held that South Africa had established a plausible case that Israel might be committing genocide sufficient for the grant of provisional measures.

The nature and scale of the atrocities, demonstrably capable of achieving the genocidal outcome, and the genocidal rhetoric together constitute strong evidence of a specific intent to destroy the group in whole or part.

Although the ICJ did not direct Israel to cease its military operations, it directed it to take measures to: i) prevent genocide; ii) ensure that its military does not commit any genocidal acts; iii) prevent and punish the direct and public incitement to commit genocide; and iv) enable the provision of urgently needed basic services and humanitarian assistance.

On 28 March 2024, the ICJ issued a second provisional order, noting that since January 2024 the situation had deteriorated with unprecedented levels of food insecurity and an increasing risk of epidemics and famine. It thus directed Israel to take measures to ensure the unhindered provision at scale of urgently needed basic services and humanitarian assistance and that its military does not commit acts (in violation of the Genocide Convention) preventing the delivery of urgently needed humanitarian assistance.

The Special Rapporteur (SR) on Palestine delivered her report to the Human Rights Council on 25 March 2024. As a point of departure, the SR maintains that the displacing and erasing of the indigenous Arab presence in Palestine has been an inevitable part of the forming of Israel as a Jewish state; and “the settler-colonial project through military occupation has stripped the Palestinian people of their right to self-determination”.

After analysing the patterns of violence and Israel’s policies since 7 October 2023, the SR concluded that there are reasonable grounds to believe that the threshold indicating Israel’s commission of genocide is met.

Remarkable intervention

The Special Rapporteur’s report was followed by a truly remarkable intervention in the United Kingdom. In early April 2024, 600 lawyers in the UK, among them Lady Hale, the former President of the Supreme Court (the most senior judge in the UK judiciary), and two other justices of that court, Lord Sumption and Lord Wilson, along with nine other judges and 69 senior barristers, addressed a letter to the Prime Minister of the UK to remind him of the UK Government’s obligations under international law.

After reviewing the evidence of genocide and the findings of the ICJ and the SR, the 600 lawyers proclaim that the UK, as a party to the Genocide Convention, is obliged to ensure that acts of genocide are prevented.

The 600 lawyers advise that the proscription of genocide (as a peremptory norm of international law) is absolute and the UK’s obligations to prevent genocide are not abrogated by the breaches of international humanitarian law committed by Hamas on 7 October 2023 or by Hamas’ ongoing holding of hostages.

The lawyers further reminded the Prime Minister that failure to comply with the obligation to take all reasonable measures to prevent genocide will incur UK state responsibility (on the part of the government and individual officials) for the commission of an international wrong, for which full reparation will have to be made under international law.

The letter accordingly calls on the Prime Minister to take various actions including imposing sanctions upon persons inciting genocide against Palestinians, suspending the provision of weapons to Israel and the possible suspension of the UK’s bilateral trade agreement with Israel.

The UK Prime Minister will be well advised to take heed of this weighty legal advice from Britain’s best legal minds. We wait to see what action will follow. If no, or insufficient, steps are taken, the spectre arises that British officials whose actions facilitate the alleged genocide in Gaza may find themselves in contravention of Article III of the Genocide Convention for aiding and abetting (complicity in) genocide.

Not surprisingly, there are now reports that trade unions in the UK are advising their members in the relevant departments of the civil service not to facilitate arms sales to Israel. That too is probably good advice. The Foreign Secretary, Mr David Cameron, has publicly indicated that at this stage the UK will not deviate from its existing practice of issuing permits.

The process to hold governments accountable for aiding and abetting genocide, along the lines envisaged by the 600 UK lawyers, has already commenced in earnest. On 1 March 2024, Nicaragua filed an application at the ICJ instituting proceedings against Germany for alleged violations of its obligations under the Genocide Convention and the Geneva Conventions. Argument was heard by the ICJ on 8 and 9 April 2024 and judgment has been reserved.

The application requests the ICJ to declare that Germany has contributed to the commission of genocide by rendering aid or assistance to the military operation in Gaza, in particular by providing political, financial and military support to Israel fully aware that military equipment provided by Germany to Israel will enable Israel to perpetrate genocidal acts and other atrocities.

The application also challenges the legality of the decision of the German Government to cut off assistance to UNRWA, the most important “relief bringer” to millions of Palestinians, thus jeopardising any effective assistance being given to the victims of the atrocities that Israel is allegedly committing with the aid of Germany. Nicaragua is accordingly requesting the ICJ to grant provisional measures directing Germany to: i) immediately suspend its military assistance to Israel; ii) make every effort to ensure that weapons already delivered to Israel are not used to violate international humanitarian law; and iii) reverse its decision to suspend the funding of UNRWA in compliance with its obligations to prevent genocide.

Effective sanctions

In the light of these remarkable legal developments the ICJ will be challenged to find effective sanctions. The record now points to a strengthening of collective will in the international community to take measures against Israel and its allies.

Several Western countries have recently suspended arms sales to Israel. Calls are increasingly made to invoke Article 6 of the UN Charter to expel Israel from the UN. It seems likely that the US and the UK would invoke their veto in the Security Council to prevent Israel’s expulsion.

However, in the light of the US and the UK on 25 March 2024 failing to veto UN Security Council Resolution 2728 calling for an unconditional ceasefire, it is not altogether inconceivable that Article 5 of the UN Charter could be invoked rather to suspend Israel from the exercise of its UN rights and privileges and for their restoration to be made conditional upon Israel desisting with unlawful conduct and making reparations in relation to its military operation in Gaza.

A longer more sustainable resolution, of course, would be the attainment of the two-State solution favoured by the international community. Some are urging for the unilateral imposition of the two-State solution by UN resolution, in keeping with the spirit of any residual obligations under the British Mandate for Palestine which formally expired in 1947.

Alternatively, the present conflict may present a good moment to resurface proposals to internationalise Jerusalem giving it a status in international law similar to the Vatican City. This would involve placing Jerusalem under the administration of the United Nations to ensure it remains a neutral and open city accessible to all religious groups (a powerful symbolic act of reconciliation among the three Abrahamic religions).

That proposal has obviously met with difficulty in the past due to the complex historical, religious and political dynamics. However, in light of recent events, this could be the moment for reigniting the campaign in the best interests of the international community as a whole. DM