WASHINGTON — On Saturday, President Obama stood with the parents of Sgt. Bowe Bergdahl in the White House Rose Garden — a voluntary media event — to announce the deal that exchanged five Taliban detainees for Bergdahl’s release. Days later, that feel-good event stands in contrast to the deal’s reception, with reports from soldiers he served with that Bergdahl may have been a deserter, and lawmakers demanding to know why the administration did not notify Congress of the deal in advance. Tommy Vietor, one of Obama’s former top aides, said Tuesday the goal of Saturday’s event was to get in...