Obama administration officials refused to fully explain to key senators the justification for freeing five senior Taliban leaders that the White House had once considered to be among the most dangerous prisoners being held in the Guantanamo Bay prison camp, according to senior Senate insiders familiar with a closed-door briefing held Tuesday for members of the Senate Foreign Relations Committee. Top Obama administration officials continued to defend the decision to skirt U.S. law and not inform Congress about the deal, telling lawmakers that “it was worth it; period,” according to one Senate insider familiar with Tuesday’s classified briefing. Officials maintained...