A key part of the White House's plan to fight the Islamic State includes vetting, training and arming a group of Fighters willing to wage a ground war in Syria that the United States doesn't want for itself. The problem is, military and security experts said, that militants in Syria have shown that ** amount of U.S. influence will stop them from fighting for their own interests, and there is ** way to guarantee that American ******* won't wind up with people they were intended to kill.