WASHINGTON (AP) -- Special prosecutor Patrick Fitzgerald's CIA-leak inquiry is focusing attention on what long has been a tactic of U.S. President George W. Bush's administration: slash-and-burn assaults on its critics, particularly those opposed to the president's Iraq war policies.If top officials are indicted, it could seriously erode the administration's credibility and prove yet another embarrassment to Bush on the larger issue of how he and his national security team marshaled information -- much of it later shown to be inaccurate -- to support their case for the U.S.-led invasion of Iraq in March 2003.The grand jury is concluding a 22-month investigation of whether administration officials illegally leaked information disclosing the identity of an undercover CIA officer, Valerie Plame, in an effort to discredit her husband, former diplomat and war critic Joseph Wilson.Anxiety at the White House increased after Bush adviser Karl Rove's fourth appearance last week before Fitzgerald's grand jury, and with a New York Times reporter's firsthand account of her dealings with I. Lewis "Scooter" Libby, Vice President Dick Cheney's top aide.Undersecretary of State Karen Hughes, the Bush administration's public diplomacy chief and a longtime Bush confidante, said, however, that the White House was not distracted by the investigation. "It's not something that's affecting the daily business of the White House," Hughes said in a taped interview aired Tuesday on NBC's "Today" show. "It's business as usual."The piece by reporter Judith Miller also fueled speculation that Fitzgerald was seeking to determine whether Cheney played a role in a campaign to discredit Wilson."The grand jury investigation has the possibility of really shining a light on the credibility of the administration, how officials tried to undermine those who were criticizing them and how they then covered up that attempt," American University political scientist James Thurber said."The question of whether the vice president was involved, we'll probably never know. But it was pretty close to him," said Thurber. He questioned whether Rove and Libby would have operated "on their own" in discussing Wilson's wife with reporters.White House officials have had quiet discussions about what to do if any Bush aides are charged. There is a general expectation that a staffer would resign if indicted.Wilson had written a newspaper essay, published July 6, 2003, that sought to undermine the administration's earlier claims that Iraq had sought to buy uranium "yellowcake" from Niger to help it build nuclear bombs.It came at a particularly difficult time for the president and his aides. The war clearly was not going well, despite Bush's "mission accomplished" speech two months earlier. And Bush was already reeling from criticism over mentioning the African yellowcake connection -- which turned out to be based on faulty British intelligence -- in his State of the Union address.While the president and his top aides refuse to comment now on the investigation, or on any issues surrounding the unfounded Iraq-African uranium claim, they were not so tightlipped in July 2003.During a presidential trip to Africa just days after Wilson's article appeared, then-national security adviser Condoleezza Rice -- now the secretary of state -- spent nearly an hour with reporters on Air Force One trying to put blame for the faulty State of the Union conclusions on the CIA and its then-director, George Tenet.Bush was also talkative then. "I gave a speech to the nation that was cleared by the intelligence services," he told reporters during a stop in Uganda.Some analysts suggest that any administration plot to undermine Wilson privately only mirrored Bush and Rice's open efforts to undermine Tenet on the same subject."This is an administration that was trying to play hardball at every level," said Michael O'Hanlon, a foreign policy scholar at the Brookings Institution. "And that's what they were doing with Wilson. And he of course was playing hardball, too. It was an ugly back and forth."Plame was named by columnist Robert Novak on July 14, 2003, as a CIA operative on weapons of mass destruction. Novak wrote that "two senior administration officials" had told him that Plame had suggested her husband, a former ambassador, be sent to Niger in 2002 to check out reports that Saddam Hussein was shopping for uranium.The reports had no basis in fact, something Wilson reported back to a Bush administration that ignored his conclusions, Wilson later wrote.In her account in Sunday editions of The New York Times, Miller, who spent 85 days in jail before agreeing to speak to the grand jury, wrote that Fitzgerald asked her questions about Cheney. "He asked, for example, if Mr. Libby ever indicated whether Mr. Cheney had approved of his interviews with me or was aware of them," she wrote.Such a question could suggest the prosecutor was investigating whether Cheney was part of a conspiracy to discredit Plame and Wilson."The answer was no," Miller wrote.While Bush vowed as recently as July to fire anyone on his staff found to have committed a crime in the CIA-leak matter, he has since completely clammed up."I've made it very clear to the press that I'm not going to discuss the investigation," Bush said Monday when asked by a reporter whether he would remove an aide under indictment. "There's a serious investigation. I'm not going to prejudge the outcome of the investigation."Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.