Russia’s invasion of Ukraine has unleashed a humanitarian catastrophe, but Ukraine is only the most visible example of contemporary conflicts subjecting populations to systematic violence and depriving them of life-saving humanitarian assistance. In Ethiopia, Sudan, Yemen, and the Democratic Republic of the Congo, the eroding purchase of international humanitarian law, combined with intensifying geopolitical competition and the rapidly changing character of modern warfare, have put enormous strain on humanitarian actors. An issue of Daedalus explores the conflicts and the implications.