'Degrade and Destroy' chronicles the U.S. war against ISIS

When the Obama administration withdrew U.S. forces from Iraq in 2011, it declared it was turning the tide of war. But by 2014, the group that calls itself the Islamic State seized territory across Iraq and Syria. Reluctantly, the U.S. went to war again using a new approach. These details are captured in a new book "Degrade and Destroy." Author Michael Gordon joins Nick Schifrin to discuss.