Patrick Fitzgerald, the U.S. Attorney for the northern district of Illinois, has been tapped to lead the probe. The recusal makes Deputy Attorney General James Comey the acting attorney general for the purposes of the case.
The Justice Department is investigating whether someone at the White House, State Department or Pentagon leaked the name of a CIA agent to punish her husband, Joseph Wilson, a former ambassador who criticized the administration's case for war in July.
"The attorney general in an abundance of caution believed that his recusal was appropriate based on the totality of the circumstances and the facts and evidence developed at this stage in this investigation," Comey said. He did not reveal exactly what led Ashcroft to make that decision.
"It's fair to say that an accumulation of facts … has led us to this point," Comey said, saying the recusal decision had developed over the past week but was only formalized Tuesday.
Comey said after Ashcroft recused himself, Comey determined that it would be "appropriate to appoint a special counsel from outside our normal chain of command," leading him to name Fitzgerald.
Comey said the move to appoint a special counsel from outside DOJ headquarters might be overly cautious, but was necessary because, for homeland security reasons, Comey and other top Justice Department officials in Washington meet often with national security officials who might be important to the case.
However, Comey said, he deemed it was not appropriate to name an outside prosecutor to handle the case. Comey promised that Fitzgerald, whom he picked, would have "the tools to conduct a completely independent investigation."
Fitzgerald earlier this month announced the indictment of former Illinois Gov. George Ryan on federal charges of taking payoffs, gifts and vacations in return for government contracts and leases while he was governor and secretary of state.
It is the first time Ashcroft is stepping aside from a high-profile Justice Department probe. His predecessor, Janet Reno, appointed several prosecutors to oversee probes of the Clinton administration.
Wilson had gone to Niger in 2002 to check an allegation that Iraq tried to buy uranium there. He reported finding no evidence.
Nonetheless, President Bush made the allegation in his January 2003 State of the Union address. When Wilson wrote in July about his findings in Niger, the White House withdrew the allegation.
Two weeks later, columnist Robert Novak named Wilson's wife as a CIA operative, quoting two administration officials. Those officials may have violated a law against identifying clandestine operatives.
The investigation stems from a CIA complaint this summer about the Wilson leak.
Justice gets about 50 such complaints from the CIA each year about leaks of classified information and few ever get beyond a preliminary investigation.
The leaker could be charged with a felony if identified.
Novak wrote that he got the name from "two senior administration officials." He said the CIA confirmed her role and "asked me not to use her name, but never indicated it would endanger her or anybody else."
The FBI has interviewed more than three dozen Bush administration officials, including political adviser Karl Rove and press secretary Scott McClellan.
The interviews have extended beyond the White House to other government agencies. The Defense and State departments and the CIA itself also are part of the probe.
The focus, however, remains on the White House, two law enforcement officials said on condition of anonymity. While the initial, informal interviews have yielded no major breaks, the FBI is satisfied that the dozen agents assigned to the probe are making progress and have not encountered any stalling tactics, the officials said Thursday.
So far, no grand jury subpoenas have been issued, they said.
Boxloads of documents have been forwarded to the FBI team, including White House phone logs and e-mails. More documents are being produced, as the contents of individual items sometimes lead agents to request additional materials, one official said.
Democrats have contended the Bush Justice Department cannot fairly investigate the Bush White House and have called for a special counsel to look into the matter. The Justice Department has said it was "not closing any legal doors" on the matter.
Wilson said he had no idea why Ashcroft chose to recuse himself now. He speculated that Ashcroft, who has long ties to members of the president's staff, simply wanted to make sure that any findings at the end of the investigation are not tainted by even the suspicion of conflict of interest.
"It's not a question of whether I'm happy about it," Wilson said. "The crime that was committed was not committed against me or my wife, but against my country. It's the country that's the victim in this."
Wilson has alternately suggested Rove leaked the name or condoned the leaking. The White House denies any involvement by Rove.
Rove's political consulting firm received $300,000 from Ashcroft's 1994 Senate campaign, and Rove donated $1,000 to Ashcroft in 1999 — one of only five candidates Rove supported financially during the period covered by Federal Election Commission records.