International humanitarian law, also known as the law of armed conflict, is supposed to spare civilians from the worst calamities of conflict. The aim of this body of law has always been clear: Civilians not involved in the fighting deserve to be protected from harm and to enjoy unimpeded access to humanitarian aid. In the Israel-Hamas war, the law has failed. This conflict is an extreme example of the breakdown of international humanitarian law, but it is not an isolated one. The growing number of wars within states and between states and non-state actors marks a new era in warfare that has pushed the law to the breaking point. In recent years, tens of thousands of civilians have been the victims of violence in war, leaving many observers wondering if the law makes any difference at all. In this lecture, Oona Hathaway examines these developments and considers what, if anything, can be done to restore some measure of protection to civilians in times of war.