American weapons and equipment used by the Syrian Democratic Forces (SDF) in the fight against ISIS will need to be returned to the United States once the war is over because they were loaned — not given — to the group, the White House says. But details on when the recovery process will begin, and how it will be executed in a country embroiled in a bloody six-year civil war, remain very murky, raising skepticism among those familiar with the Pentagon’s long history of losing track of lethal machinery it lends to foreign troops.