On Saturday, President Obama announced the return of the only American soldier known to be held prisoner in Afghanistan. Army Sergeant Bowe Bergdahl was traded for five Taliban detainees at Guantanamo Bay. But the deal is not going down well with some of Bergdahl's former comrades — or with everybody in Congress. Bergdahl disappeared from his post in Afghanistan five years ago. A US Army division and thousands of Afghan soldiers and police spent weeks trying to find him. Was he a deserter? Absent without leave? Did the US negotiate with terrorists to secure his release? Eugene Fidell teaches military justice at the Yale School of Law.