International humanitarian law – the law of armed conflict – aims to constrain how wars are fought. It is designed to protect noncombatants and limit the means of warfare. As each hour brings news of further horror in the Israel-Hamas conflict, what role should international law be playing? And does it actually have any capacity to constrain the behaviour of the combatants? On October 7, the Hamas militant group launched thousands of rockets against Israel in advance of a ground attack. Militants killed more than 1,400 people and wounded 3,400 others in towns and kibbutzim across southern Israel. It was...