US, Turkey force Kurds to pull back in Northern Syria despite effectiveness against ISIS

Turkey's U.S.-backed push into northern Syria Wednesday was aimed at ISIS, but also sent Ankara's nemesis - and American ally the Kurds - retreating east of the Euphrates, making good on a vow from strongman Recep Tayyip Erdogan. Amid a fence-mending visit from Vice President Biden, Erdogan's tough …