White House staffers began Wednesday saving anything and everything to comply with a Justice Department probe into who exactly leaked the identity of a CIA employee, President Bush's spokesman said.

"At this point, all the Department of Justice has asked us to do is preserve any and all information that could be related," Press Secretary Scott McClellan (search) said. McClellan said the White House would consent, if asked, to polygraph tests for staff. "We will cooperate fully, at the direction of the president ... Full cooperation is full cooperation."

White House employees have received an e-mail from Alberto Gonzales (search), counsel to the president, urging them to save all correspondence and material since February 2002 relating to former Ambassador Joseph C. Wilson (search), his wife's position or activities at the CIA, and communication with the reporters who were involved in the alleged leak.

"[F]or the time period February 1, 2002 to the present, all documents, including without limitation all electronic records, telephone records of any kind (including but not limited to any records that memorialize telephone calls having been made), correspondence, computer records, storage devices, notes, memoranda, and diary and calendar entries," the e-mail said.

"You must preserve all documents relating, in any way, directly or indirectly, to these subjects, even if there would be a question whether the document would be a presidential or federal record or even if its destruction might otherwise be permitted," the e-mail demanded.

Syndicated columnist Robert Novak, who originally disclosed the CIA employee's identity, wrote in his column Wednesday that he regrets referring to Wilson's wife as an "operative" and that he didn't think her position was a big secret in Washington. It is not clear what position Wilson's wife actually holds at the agency.

"To protect my own integrity and credibility, I would like to stress three points," Novak wrote. "First, I did not receive a planned leak. Second, the CIA never warned me that the disclosure of Wilson's wife working at the agency would endanger her or anybody else. Third, it was not much of a secret."

Justice Department Probe Begins

The formal Justice Department investigation into the leak began Tuesday and President Bush vowed his administration's full cooperation. Bush said he himself wants to know the truth and he's ordered aides to cooperate. He promised that anyone found to be responsible "will be taken care of."

"Leaks of classified information are bad things. We’ve got too much leaking in Washington," Bush said during a Tuesday stop in Chicago. "I want to know who the leakers are."

The investigation involves looking into charges that senior White House officials blew the CIA employee's cover after her husband publicly questioned Bush's claim in his State of the Union address -- based on British intelligence reports -- that Iraq had tried to buy uranium in Africa.

The White House later acknowledged that the U.S. intelligence community should have confirmed the report before including it in Bush's address.

Democrats on Tuesday demanded that a special counsel be called in to investigate but Bush said he's "absolutely confident" that Justice prosecutors can do the job. Democratic leaders argued that Attorney General John Ashcroft was too close to the White House to run an independent investigation.

"If there ever was a case for the appointment of a special counsel, this is it," said California Rep. Nancy Pelosi, the House Democratic leader.

But Ashcroft has not ruled out the possibility of appointing a special counsel, according to one senior law enforcement official.

"I have told our administration, people in my administration, to be fully cooperative," Bush said Tuesday.

McClellan said Wednesday that Bush believes the Department of Justice is the right place for the investigation.

"The Justice Department is interested in getting to the bottom of this. So are we. If a crime was committed, DOJ is the appropriate agency to investigate this," McCleellan said.

Sen. Arlen Specter, R-Pa., said in a television interview Wednesday he doesn't believe there has to be an outside investigation and that an effort by career counterespionage lawyers and FBI agents already is under way.

Specter, who is a member of the Senate Judiciary Committee, said that panel can conduct its own probe.

"We have quite a few members on the committee who are former prosecutors and we can take a look at it and see to it that it is being conducted in an appropriate way," he said.

Who's Leading the Charge?

The probe for now is in the hands of 11 Justice Department lawyers led by John Dion, chief of the counterespionage section of criminal division. Dion's team handles all of the roughly 50 referrals a year from the CIA and other intelligence agencies about leaks of classified information.

The decision to begin the investigation was made Friday by Dion.

FBI counterintelligence agents from the Washington field office will conduct the interviews and examining documents and e-mails.

Justice's counterespionage section was waiting for the answers to a list of 11 questions from the CIA before deciding whether to launch a full-scale criminal investigation. This list, approved in 1969 by FBI Director J. Edgar Hoover, is what Justice uses in such leak probes. Questions include what effect the disclosure of the classified data could have on national security.

Wilson traveled to Niger in 2002 to investigate allegations of uranium sales to Iraq. He concluded the allegations were not credible. On July 6, 2003, he wrote a commentary in The New York Times that said some intelligence related to Iraq's nuclear weapons program was "twisted to exaggerate the Iraqi threat."

Federal law prohibits the unauthorized disclosure of a covert agent's name, punishable by up to 10 years in prison. The CIA officer's name was published by Novak, who said he based his report on two senior administration officials.

In his column Wednesday, Novak defended why he disclosed Wilson's wife's name. He said a CIA official talked to him about why Wilson, a Clinton administration worker, was sent to Niger. That CIA official did in fact ask that the Wilson's wife's name not be used, saying she probably never again would be given a foreign assignment and that "exposure of her name might cause difficulties" if she travels abroad, Novak wrote.

"He never suggested to me that Wilson's wife or anybody else would be endangered," the columnist wrote. "If he had, I would not have used her name. I used it in the sixth paragraph of my column because it looked like the missing explanation of an otherwise incredible choice by the CIA for its mission."

Newsday Editor Howard Schneider said Tuesday evening his newspaper has had no contact with the White House or Justice Department about the memo. He said, however, that Newsday was probably singled out because the newspaper was the first to report that a CIA employee revealed in Novak's July column was said to be an undercover operative.

Fox News' Anna Stolley and The Associated Press contributed to this report.