Support WBURBig Changes And Major Dilemmas Loom In Next Phase Of ISIS War In SyriaPlay04:48Download AudioTom BowmanAlice FordhamAlison MeuseMarch 23, 2017 ShareU.S.-backed Syrian Democratic Forces, made up of an alliance of Arab and Kurdish fighters, regroup on the northern outskirts of Deir Ezzor as they advance to encircle the ISIS bastion of Raqqa on Feb. 21. (AFP/Getty Images)