Ten years ago, as Mosul, Iraq’s second-largest city, fell to ISIS, the creation of dozens of militias was seen as a way to mobilise and organise the Shia youth who had risen up en masse to fight the jihadist group and defend Baghdad, which was under threat. These militias were supposed to be a temporary force. Instead, they were never demobilised, driving the Iraqi state towards ever-greater instability. How did these militias become such powerful strategic players in post-ISIS Iraq?