Missouri Teen Shooting, Upheaval in Iraq, Obama-Hillary Rela

The investigation into the shooting death of an unarmed Missouri teen, the fast-changing developments in Iraq and the status of the U.S. humanitarian rescue mission, and the reported rift between Hillary Clinton and President Obama over U.S. foreign policy. Joining Gwen: Yochi Dreazen, Foreign Policy Magazine; Carrie Johnson, NPR; Jeff Zeleny, ABC News