Bush, Bergen writes, was “incensed” when Michael Morell, his CIA briefer, told him in early 2002 that bin Laden had survived the Tora Bora attacks, and “became hostile, as if Morell himself were the culprit.”

In 2005, Bergen reports, a paper written by a CIA analyst became the guide for the ultimately successful hunt. With the absence of any plausible leads after nearly four years, the analyst proposed building the search on four “pillars” — bin Laden’s family, his communications with top al-Qaeda leaders, his occasional outreach to the media and his use of a courier network.

It was the now widely known discovery and years-long tracking of the courier Abu Ahmed al-Kuwaiti, who lived inside the compound with bin Laden, that ultimately cracked the case.

As they debated how to find out whether bin Laden was inside, the CIA discussed numerous proposals.

“One idea was to throw in foul-smelling stink bombs to flush out the occupants,” Bergen says. Another was to use loudspeakers outside to broadcast from a purported “voice of Allah” commanding them to come into the street. Others proposed establishing a nearby safe house. That idea was adopted but provided agents with little information about what, or who, was inside.

When Obama met with his top aides April 28, two days before the raid, both Gates and Vice President Biden reiterated their opposition to the operation as too risky. Bergen writes that they argued that the evidence of bin Laden’s presence was circumstantial, the mission was too dangerous and relations with Pakistan would be destroyed.

Gates has publicly acknowledged reservations. At the final April 28 White House meeting before the raid, Bergen says, Gates told Obama he would be “more comfortable” with “some kind of precision strike” rather than a commando raid.

After Obama gave the formal go-ahead two days before the May 1 mission, White House aides continued to debate whether he should attend a media dinner the night of the raid and whether his presence in the Situation Room during the operation would give the unwelcome impression that the chief executive was “micromanaging” a military operation.