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 rhetoric against the Kurds, a reliable and effective American partner in the fight against ISIS, appeared to force the U.S. to choose sides in the separate, and longstanding fead between its allies. --More...