The decision to attack had been made days earlier by the President. He gathered his senior intelligence, military and diplomatic team together in the Situation Room on Thursday afternoon to hear his options. There were already concerns about operational security. At that point, hundreds of people had already been read into the potential whereabouts of bin Laden. Any leak would have ruined the entire mission.

The intelligence professionals said they did not know for sure that bin Laden was in the compound. The case was good, but circumstantial. The likelihood, officials told the President, was between 50% and 80%. No slam dunk. Obama went around the table asking everyone to state their opinion. He quizzed his staff about worst case scenarios–the possibility of civilian casualties, a hostage situation, a diplomatic blow-up with Pakistan, a downed helicopter. He was presented with three options: Wait to gather more intelligence, attack with targeted bombs from the air, or go in on the ground with troops. The room was divided about 50-50, said a person in the room. John Brennan, the President’s senior counter-terrorism adviser, supported a ground strike, as did the operational people, including Leon Panetta at the CIA. Others called for more time. In the end, about half of the senior aides supported a helicopter assault. The other half said either wait, or strike from above.

Obama left the meeting without signaling his intent. He wanted to sleep on it. At about 8:00 a.m. on Friday, just before he boarded a helicopter that would take him to tour tornado damage in Alabama, Obama called his senior aides into the Diplomatic Room. He told them his decision: A helicopter assault.