"There was a desire to make a clean break with the policies of the Bush administration. ... They had to bring someone in from the outside," said one senior aide at the Senate Intelligence Committee who asked for anonymity to discuss a nominee seeking confirmation from the panel.
John Brennan, a former senior CIA counter-terrorism official who originally was being considered for the post, ruled himself out after a storm of protest from some Obama supporters occasioned by his tenure at the agency during a time when it used interrogation techniques like water-boarding -- simulated drowning -- that critics label torture.
"They allowed the bloggers to dictate that they couldn't appoint anyone" who had served at the agency during the Bush administration, said a former senior CIA official. The former official called the pick "pretty good … given the hand they dealt themselves."
"If you rule out anyone who had been there in the last eight years," the former official continued, "you limit the universe of people" from which you can choose.
He said that, at 70 years old, Panetta was likely "not thinking about his next job" after heading the agency -- an important qualification. "If you stay there (as director) for any length of time -- well, let's just say you don't make many new friends."
Nonetheless, the former official said, choosing an outsider was "not ideal."
Even those who support the pick acknowledge that Panetta -- as someone who has not had access to current intelligence for many years -- will have, in the words of the Senate Intelligence Committee aide, "a very steep learning curve."
"He'll have to get up to speed very quickly on the hot spots (like Afghanistan-Pakistan, North Korea and Iran) -- who is who and who is doing what … how we are collecting against those targets," said the aide.
In addition to the substantive aspects of the job, the new director, if confirmed, will have to swiftly learn his way around the agency, familiarizing himself with the way it is organized and how it operates on a day-to-day level.
"The value of an insider is that they know how things run and what questions to ask," said a senior U.S. national security official who asked for anonymity because he is not authorized to speak to the media.
"In any agency," the Senate aide said, "the career bureaucrats know everything," and this can make things difficult for an outsider, especially if he does not enjoy their trust.
In this context, some observers say Panetta should move to reassure agency staff that he will support them, especially given concerns about possible investigations by the incoming administration into CIA practices like interrogation and rendition.
These concerns have been stoked by the suggestions from some Democrats that the appointment of an outsider is designed in part, as Sen. Ron Wyden, D-Ore., put it, "to usher in a new era of accountability" at the agency.
In a statement issued last week, Wyden, a senior member of the Senate Intelligence Committee, added: "For too long our nation's intelligence community has operated under a policy of questionable effectiveness and legality. … I look forward to working with Mr. Panetta to declassify much of the story of what went wrong at the CIA these last eight years."
"People (at the CIA) don't know him. … There are a lot of unknowns," said the national security official.
"He will have to reassure the rank and file that he believes in them. … They need to be comforted," added the official, urging Panetta to hold a series of "all hands" meetings for staff and to arrange in short order a visit to the agency's headquarters by the president himself.
To help reassure CIA staff, Panetta also is being urged to keep intact the leadership team around outgoing Director Michael Hayden, including especially his deputy, Steven Kappes, a veteran spy popular at the agency who was brought back by Hayden after quitting following a clash with the previous director, former Rep. Porter Goss, R-Fla.
"I have very high regard for Steve Kappes," another Intelligence Committee member, Sen. Evan Bayh, D-Ind., said in a statement. He added that he was "impressed by (Kappes') competency."
"I hope we can convince both Mr. Panetta and Mr. Kappes to work together at the CIA," concluded Bayh.
The former CIA official said that even if Panetta were able to get up to speed and win the support of staff, he still would suffer from being an outsider.
"There's a unique culture" at the CIA, the former official said. "It takes a while to learn how to decipher what you are hearing and seeing."
"You wouldn't make someone commandant of the Marine Corps if they'd never been in the military," the former official concluded.
But the historical record appears more mixed than this observation would suggest.
The man after whom the CIA headquarters building is now named, the first President George Bush, described himself as a "total outsider" to intelligence when he took over the agency.
"I viewed my job not to learn all the tradecraft, but to defend the quality and the character of the agency and the people there," Bush told Fox News Sunday. "That was perhaps an easier assignment than knowing all about every intrigue of intelligence."
George Tenet, though he had worked for the Senate Intelligence Committee and the National Security Council, had worked at the CIA for only 18 months as deputy director when President Bill Clinton tapped him to head the agency.
On the other hand, James Woolsey and John Deutch, the two other outsiders who headed the agency under Clinton -- and during Panetta's last stint in government -- are widely regarded as having much less successful tenures. Woolsey declined comment through an aide, and Deutch did not respond to a telephone message asking for an interview.
"All I hope," former President Bush said, "is that whoever goes out there goes with confidence in the CIA, and the people around CIA, they're good people." He said he had "great confidence" in Obama's pick.