But, by choosing him, Obama has given both liberals and conservative Republicans an opportunity to re-open the debate over Bush administration interrogation policies.
In a 2007 CBS television interview, while Brennan was out of government, he appeared to assert that enhanced interrogation techniques had produced useful information. "There have been a lot of information that has come out from these interrogation procedures that the agency has in fact used against the real hardcore terrorists. It has saved lives," he said.
Inside the CIA, where career intelligence officers consider it a point of pride to be above politics, employees will want to see whether Brennan's time at the White House has made him a more political figure.
"He will have to overcome the impression that he has become a political player who overachieved in spinning things to favor the president at the expense of the agency," a former CIA official said on condition of anonymity.
Shortly after the Navy SEAL raid that killed bin Laden, Brennan briefed the press, telling them that the al Qaeda leader had been killed in a firefight and had tried to use one of his wives to shield himself from the attackers.
"Here is bin Laden, who has been calling for these attacks, living in this million-dollar-plus compound, living in an area that is far removed from the front, hiding behind women who were put in front of him as a shield," he said at the time. "I think it really just speaks to just how false his narrative has been over the years."