More than seven years after Baghdad’s declaration of victory over the Islamic State group (IS), tens of thousands of women and children—including family members of accused militants—continue to languish in camps in Iraq and Syria. The largest of these sites is Al-Hol in Syria, located 13 km (8 miles) from the Iraqi border, which is controlled by the US-backed Syrian Democratic Forces (SDF).

Ongoing reports of violence and deteriorating conditions in the camp have led to calls for its closure, and the repatriation of those...