Islamist move into Kurdish territory changes U.S. equation

The White House is weighing launching airstrikes and sending humanitarian aid as the crisis darkens for displaced Christians and Yazidis fleeing Islamist militants in northern Iraq. Karen DeYoung of The Washington Post joins Hari Sreenivasan to discuss how the rationale for U.S. military assistance has shifted, and the events that have pushed the U.S. to its tipping point.