Eight months earlier, on a hot day in August, Tom Donilon, then the deputy national-security adviser, had added a brief item to the end of his daily morning briefing for Barack Obama. He said, “Leon and the guys at Langley think they may have come up with something”—something related to bin Laden.

There had been no scent of the al-Qaeda leader for more than eight years, ever since he had slipped away from the mountain outpost of Tora Bora during a botched siege by allied troops. The Bush administration maintained that he was somewhere in the mountainous regions of northwestern Pakistan, but, in truth, they had no idea where he was. On May 26, 2009, Obama had concluded a routine national-security briefing in the Situation Room by pointing to Donilon, Leon Panetta, his newly appointed C.I.A. director, Mike Leiter, director of the National Counterterrorism Center, and Rahm Emanuel, his chief of staff. …

Obama said, “Here’s the deal. I want this hunt for Osama bin Laden and [Ayman] al-Zawahiri to come to the front of the line. I worry that the trail has gone cold. This has to be our top priority and it needs leadership in the tops of your organizations.” He added, “I want regular reports on this to me, and I want them starting in 30 days.”