Aaron Y. Zelin writes: Over the weekend, dozens of pictures trickled out on one of the official Twitter accounts of the Islamic State of Iraq and al-Sham, the jihadist group currently setting off a panic in vast swathes of northern Iraq. The graphic photographs, according to ISIS, showed mass executions of Shiite soldiers who had fought in the Iraqi government’s military and security forces. In the images, ISIS fighters corral hundreds of individuals into trucks, forcing them to lie down in shallow graves with their heads to the ground, and then shooting them with Kalashnikovs.

ISIS claimed it had killed more than 1,700 people, though the pictures account for a few hundred at most. Though shocking, this level of brutality is hardly new for the extremist Sunni group, as it has attempted to provoke the Shiite population going back to last decade, when the volatile Abu Musab al-Zarqawi was its leader.

ISIS subscribes to takfir, a practice according to which it believes it is legitimate to kill a Muslim who has abandoned its hard-line interpretation of Islam. Last decade, when ISIS was under the control of Zarqawi and was then called Al Qaeda in the Land of Two Rivers (better known as Al Qaeda in Iraq, or AQI), it used takfir to justify the murder of not only the Shiite population of Iraq but also other Sunnis who did not follow AQI’s narrow and severe interpretation of Sharia, or Islamic law. (This broad use of takfir ended up backfiring against AQI, since most Iraqi Sunnis did not want to live under such an oppressive group.)

So ISIS, the latest incarnation of AQI, has religious reasons for massacring Shiites, all of whom it views as apostates. And there’s another motivation for it as well: old-fashioned vengeance. As ISIS’ official spokesperson noted in an audio message posted June 11, “It is true that between us revenge awaits … a long and heavy revenge awaits. However the revenge shall not be in Samara or Baghdad, but rather it shall be in Karbala the city made ?lthy, and in Najaf the polytheist city, so wait.” (Karbala and Najaf are important Shiite shrine cities.) So in ISIS’ estimation, its attacks on Shiites are merely retaliation for the Iraqi government’s actions against Sunnis.

But there’s also a strategic reason behind the executions — and the gruesome pictures posted online for all to see. ISIS’ goal is not only to scare Iraqi Shiites but to provoke them to radicalize, join Iranian-sponsored militias and then commit similar atrocities against Sunnis. ISIS then hopes to set itself up as the protectors of the Sunni population, helping to consolidate its hold on Sunni population centers. [Continue reading…]