Shi’ite militias are heavily engaged in the fight against the Islamic State and, alongside more mainstream units in the Iraqi army as well as Kurdish peshmerga, are advancing on territory formerly held by the Islamic State especially in the vicinity of Tel Afar. This has led to a lot of handwringing in the United States and Europe about whether the Popular Mobilization Units consisting of those who answered Grand Ayatollah Ali Sistani’s call to defend against the Islamic State are bent on sectarian vengeance.
Consider, for example, this recent report by the Associated Press: