Given the personal problems that have faced Petraeus and now perhaps Gen. John Allen, the outgoing commander in Afghanistan, character issues will surely weigh heavily in Obama's considerations.

There are others whom Obama might pick to run the CIA, such as John Brennan, his top counterterrorism adviser, who had a distinguished career at the agency, including a tour as station chief in Saudi Arabia and who also led both the Terrorist Threat Integration Center and its successor, the National Counterterrorism Center, following the 9/11 attacks.

Brennan, a no-nonsense graduate of Fordham who speaks Arabic, was Obama's first pick for CIA director in 2008 but withdrew his name from consideration after it became clear that his nomination hearings would be complicated by some in Congress who would grill him about the waterboarding of detainees in CIA custody and the agency's prisons overseas.

It's also not clear why Brennan would want the CIA job given the fact that in his present position he gets to see the president far more often than any CIA director, and from his windowless office in the basement of the West Wing of the White House, he has dominated U.S. counterterrorism policy on issues such as drones, Pakistan, Yemen and the hunt for al Qaeda's leaders, including bin Laden.

Another plausible candidate is Michael Vickers. He had a storied career at the CIA, where as a young man he was the agency's principal military strategist on the Afghan "account" during the 1980s war against the Soviets. Vickers helped to funnel vast numbers of weapons through the Pakistanis to the various Afghan mujahedeen groups that defeated the Soviets.

Vickers' doctorate in military history from Johns Hopkins and owlish exterior mask the fact that he is a risk taker, albeit in a calibrated, cerebral way. He left the CIA when he was only 32, having already played a key role in the most successful covert operation in the agency's history -- expelling the Soviets from Afghanistan -- to get an MBA at Wharton. And he was a Special Forces officer in Central America.

Like both Morell and Brennan, Vickers also played a key role in the operation to find bin Laden. In his previous job at the Pentagon, he was the civilian overseer of Special Operations Forces and was intimately involved in the planning of the SEAL raid in Abbottabad. But unlike Morell and Brennan, Vickers wasn't at the CIA when waterboarding and other coercive interrogation techniques were being employed by the agency.

Given all the consternation on Capitol Hill about the circumstances surrounding the attack on the U.S. Consulate in Benghazi, Libya, in September in which the U.S. ambassador was killed along with two CIA employees, the Obama administration could decide to tap someone who has deep experience on the Hill.

An obvious candidate would be Harman, who as a member of the House of Representatives from California between 1993 and 2011 served on all the major committees focused on national security: Armed Services, Intelligence and Homeland Security. Now running the Woodrow Wilson International Center for Scholars in Washington, Harman is regarded as one of the Democratic Party's leading experts on national security.

If appointed and confirmed, Harman would be the first woman director of the CIA.

A further consideration: Another former nine-term Democratic congressman from California, Panetta, now the defense secretary, led the CIA for more than two years and is regarded as one of the most effective directors of the agency in recent decades.

(Note: An earlier version of this article incorrectly said Michael Morell was executive assistant to CIA director George Tenet during the presidency of George W. Bush.)

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