WASHINGTON—The Obama administration is considering opening a network of new bases in Iraq like the hub being established west of Baghdad, the nation’s top military officer said, something that would deepen the U.S. role in the war against Islamic State. Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, outlined the possibility of several new bases across Iraq as the U.S. looks for ways to help Baghdad gain the upper hand against the extremist militants. Each base could require additional U.S. troops, but it was unclear how many or whether an overall troop increase would be needed. Gen. Dempsey’s comments, to reporters accompanying him on a trip to the Middle East and Europe on Thursday, come a day after the White House formally announced a plan to open a new training site in Anbar province , west of Baghdad. The U.S. will deploy up to 450 new troops […]