...When the meeting between the two men ended just after 4:15 p.m. on Friday, virtually everyone in the West Wing was in the White House residence at the annual holiday party for the building’s overworked staff. The leader of the free world and the ex-leader wandered a deserted hallway, past the offices of the senior advisers, only to discover the door to the press corps briefing room locked. ...Do you know how to open up the briefing room?” Mr. Obama asked the staffer, Katie Hogan. “Yeah,” Mr. Clinton said, “can you help us unlock it?” Hearing that, Mr. Gibbs walked...