Marc Weller on what international law has to say about the Israel-Hamas conflict

LAW ACCEPTS the reality that war is a feature of human relations. Hence, law in war is meant to strike a balance between the need to use force in extreme circumstances and the wish to reduce the prospect of war and keep the associated human suffering to a minimum. This balancing act takes two forms. The UN Charter limits the right of states to make war. Humanitarian law limits the means of warfare.

The UN Charter permits necessary and proportionate self-defence. But it is not always easy to determine how much force is proportionate to an armed attack and necessary to prevent the next one.

In the wake of the terrorist attacks on September 11th 2001, for instance, it was widely accepted that America enjoyed the right of self-defence, even against a non-state actor like al-Qaeda. But how much force would be proportionate to the murder of over 3,000 people in New York?

American forces were entitled to pursue and defeat al-Qaeda in Afghanistan, where Osama Bin Laden’s group was mainly based. Arguably, this included the right to go as far as overthrowing the Taliban government, which was so closely intertwined with al-Qaeda that it would have been impossible to defeat the one without at the same time taking on the other.

In response to the horrific attack of October 7th, Israel, too, is entitled to self-defence. But what is a proportionate response to the horrendous atrocity that cost some 1,400 mainly civilian lives and still exposes over 200 hostages to ceaseless terror?

Israel’s prime minister, Binyamin Netanyahu, asserts that it is necessary to eradicate Hamas as a political and military force if further outrages are to be prevented. Even if self-defence goes that far, there is still more balancing of competing values to be done under the second branch of applicable law, humanitarian law.

A civilian population remains protected by the fundamental principles of humanitarian law even in a conflict triggered by an indefensible outrage of the kind mounted by Hamas, which evidently does not play by humanity’s rules. Israel fully accepts this fact. The difficulty arises, again, with respect to proportionality—this time as an element of humanitarian law.

The first principle of humanitarian law is that of distinguishing between combatants and civilians along with the obligation to ensure the protection of civilians. Attacks must not be directed against a civilian population. This prohibition includes indiscriminate aerial bombardments of civilian areas.

Where it is impossible to isolate civilians from an attack against a lawful, military objective, proportionality requires a balancing of the military advantage gained through the attack against the extent of civilian damage it will foreseeably cause. Humanitarian law states that if “incidental loss of civilian life would be excessive in relation to the concrete and direct military advantage anticipated” then the operation must not take place.

Israel argues that, given the gravity of the threat to its national security and the lives of its citizens, this provision must not place undue restrictions on its military campaign. Sharvit Baruch, formerly a senior legal adviser to Israel’s armed forces, argues: “Even if many civilians in Gaza are harmed during the attacks”, when weighed against Israel’s overwhelming security interest in defeating Hamas “this is not necessarily excessive incidental damage and therefore [these] would not be disproportionate attacks that are illegal.”

This view would unhinge the law on the protection of civilians. The extent of its application cannot be relative, depending on the sense of injustice and threat felt by the state using force. Every state going to war will inevitably feel that its vital interests are at stake. But this becomes a judgment on how far force can be used in self-defence under the UN Charter, and not on the extent to which civilians must be protected under humanitarian law when that force is used.

Humanitarian law requires that the military advantage of each and every combat operation during conflict needs to be balanced against the risk of civilian casualties, even if vital interests of the state mounting the operation are at stake.

Colonel Baruch adds that “Since Hamas places its military infrastructure in the heart of the civilian population in the Gaza Strip, including in residential houses, schools, mosques and businesses, it is permissible to direct attacks toward these sites, as they have lost their civilian nature and have become legitimate targets due to this use.”

Again, the fact that Hamas operates from a densely populated territory does not strip the civilian population in that territory of legal protection. These are not willing human shields, even if Hamas may attempt to keep them in place through misinformation and propaganda. Attacks against Hamas can only be undertaken if there is no foreseeable risk of causing excessive civilian casualties when compared to the military advantage gained from the attacks being contemplated.

Israel asserts that it is fulfilling its duty of distinguishing between civilians and combatants by telling the population of northern Gaza to evacuate. At a tactical level, where a specific building is to be attacked, such measures may be legitimate or even legally required. However, even where Hamas has networks of subterranean tunnels, clearing out a million civilians in order to generate a clear field of fire throughout all of northern Gaza is not permitted.

Israel cannot discharge its duty of distinction between combatants and civilians simply by wishing the entire civilian population away. This may make it far more difficult for Israel to wage this war, but it cannot simply transfer the risks involved in armed combat in an urban environment from its soldiers to civilians.

The International Committee of the Red Cross has issued a declaration confirming that this displacement is incompatible with humanitarian law, especially as southern Gaza, the area to which the population is supposed to move, is also subject to attack and deprived of that which will be necessary for those living or moving to survive—unless aid arrives consistently and reliably. The refusal to allow sufficient quantities of humanitarian supplies into the area, delivered under international control and supervision, can also not be justified by whatever military advantage such a strategy is meant to yield. Even if, as Israel asserts, Hamas is secretly holding its own stocks of fuel and supplies and reserving them for war rather than for other Gazans, this cannot justify withholding from civilians, crowded together in a position of extreme vulnerability, what they need to survive.■

Marc Weller is professor of international law and international constitutional studies at the University of Cambridge. He has served as an adviser on peace negotiations in numerous countries, including Kosovo, Myanmar and Sudan. The views expressed are his own.