Chicago ? President Bush said Tuesday that he welcomed a Justice Department investigation into whether White House officials illegally disclosed the identity of a CIA agent in an effort to discredit or punish her husband, an administration critic.

Bush also dismissed calls by Democrats for the appointment of a special counsel to look into the matter. Administration critics claim that Atty. Gen. John Ashcroft is too partisan to preside over an impartial investigation.

On a campaign fund-raising trip through the Midwest, Bush said he was “absolutely confident that the Justice Department will do a very good job.”

“I want to know the truth,” Bush said. “If there is a leak out of my administration, I want to know who it is. And if the person has violated the law, the person will be taken care of.”

The remarks were the president’s first on the burgeoning scandal, which burst into view this past weekend when it was disclosed that the CIA had asked the Justice Department to investigate whether senior administration officials deliberately unmasked a CIA agent married to former diplomat Joseph C. Wilson IV, a critic of Bush’s handling of intelligence in the run-up to the war in Iraq.

The Justice Department said Tuesday that it was conducting a formal investigation into who leaked the agent’s identity to conservative columnist Robert Novak, an apparent violation of a 1982 law designed to protect intelligence operatives.

The allegations are serious; exposing the identity of a CIA operative is a felony punishable by as many as 10 years in prison. And they have handed Democrats a juicy political opportunity, enabling them to accuse the hawkish Bush administration of playing fast and loose with national security.

In the Senate, a resolution sponsored by about two dozen Democrats was introduced Tuesday calling for a “fair, thorough and independent investigation into a national security breach.”

Democratic criticism

Democrats took to the Senate floor to liken the leak to President Richard M. Nixon’s enemies list and to “knee-capping” the CIA agent in retaliation for her husband’s criticism of the administration’s policies.

“This is not just a leak; this is a crime, plain and simple,” Sen. Charles E. Schumer, D-N.Y., said.

Justice officials said they weren’t ruling out the possibility of acceding to the demands for a special counsel. Some former prosecutors said they felt the facts of the case were so murky that appointing a special counsel now seemed premature.

For now, the politically delicate task falls to a low-profile group of Justice professionals and survivors. The team is headed by John Dion, chief of the counterespionage section of the department’s criminal section, a 20-year spy-catcher who has won department awards during Republican and Democratic administrations for his work investigating turncoats and security breaches.

“John is a very aggressive prosecutor who will call it as he sees it,” said Eric Dubelier, a Washington, D.C., lawyer and former federal prosecutor who worked with Dion several years ago. “He will make a decision based on the facts and the law. Then, the question will be, ‘Who is the final arbiter?’ “

But some members of Congress said there was evidence that the investigation was going off-track.

They cited a heads-up that the Justice Department gave the White House on Monday night that it had decided to launch a formal investigation, and that it would be sending out a letter Tuesday morning explaining which documents it wanted preserved.

White House spokesman Scott McClellan said the White House counsel’s office asked whether staff should be notified immediately; the Justice officials said it could wait until the next morning.

McClellan rebuffed a question asking whether the evening phone call could be seen as advance warning, calling it a “silly suggestion.”

Schumer said the notice created an opportunity for mischief, essentially giving White House staff an opportunity overnight to destroy evidence.

Preserving documents

Legal experts said the White House probably was obliged under the law to preserve documents, given the widespread publicity the case had generated. Others said they thought the White House should have acted more aggressively in ensuring that the documents be preserved.

Later Tuesday, White House counsel Alberto Gonzalez expanded his notification to White House staff members by specifying that they preserve records of any contacts with members of the news media, including columnist Robert Novak and Newsday reporters Tim Phelps and Knut Royce.

Phelps and Royce apparently were named because a story they wrote about Novak’s column in July disclosed that Valerie Plame was an undercover operative, which Novak’s column didn’t say.

Their story also quoted Novak as saying that an administration official had sought him out with the information about Plame. Novak now tells it differently, saying that the information emerged in an interview that he requested with the administration official. The Newsday account suggests a more aggressive role by the unidentified leaker.

Under Justice Department regulations, Ashcroft has full discretion in whether to appoint a special counsel, unlike the post-Watergate independent counsel statute, which ascribed that authority to a panel of judges. Congress allowed the counsel statute to expire in 1999 amid recriminations over the expense and scope of the Whitewater investigations.