Instead of shutting down or scaling back the N.S.A.’s programs, Obama has worked to bring them into narrow compliance with rules that often contradict the views he expressed when he was a senator and a Presidential candidate. In August, he appointed a five-person panel to review intelligence policy, and the group is scheduled to issue recommendations by the end of the year. His decisions about what changes to endorse could determine whether his Presidency is remembered for rolling back one of the most controversial national-security policies of the Bush years or codifying it.