South Asia Center Nonresident Senior Fellow Barbara Slavin writes for Al Monitor on the rise of Iran-backed militias on the battlefield in Iraq and Syria:
WASHINGTON — A plethora of new and old Shiite militias is dominating battlefields in Iraq and Syria, US experts say, raising concerns about growing Iranian influence that could exacerbate sectarian divisions and ultimately weaken the fight against the group that calls itself the Islamic State (IS).
The growth of these groups — known as popular mobilization units — poses a conundrum for the Obama administration and the coalition of about 60 countries it is leading against IS. For the time being, Iran-backed groups are providing most of the “boots on the ground” that are pushing back IS forces from key areas near Baghdad, including Diyala province. These militias are also preventing IS from overrunning even more territory in Syria. But there are disturbing reports of massacres of Sunni civilian populations by Shiite fighters, some of whom have killed Americans in the past.