As Syria cease-fire fails, Obama may leave successor 'problem from hell'

By Jonathan Landay and Matt Spetalnick WASHINGTON (Reuters) - The United States was relegated to the sidelines of the Syrian war on Friday as an all-out assault by Syrian government and Russian forces on opposition-held Aleppo threatened to unleash a new refugee wave and drive U.S.-backed rebels into the ranks of al Qaeda’s Syrian branch, U.S. officials and experts said. Moscow’s direct participation in the offensive left fading hope for U.S.-Russian peace efforts, raising the likeli