Shia militants fighting ISIS in Iraq complicate country's tenuous situation

Shia militias have played a key role in driving ISIS out of the so-called Baghdad Belt of Sunni villages ringing the capital. But the sectarian militias have long been implicated in brutality against the country's Sunnis, and while they have benefited from U.S.-led airstrikes, their advance could undermine efforts to knit the troubled country together.