March 7 (Bloomberg) -- Lewis Libby's conviction on charges he lied about White House efforts to discredit Iraq war critics shatters George W. Bush's 2000 campaign vow to ``uphold the honor and the integrity'' of the presidency and intensifies his second-term political woes.

``This deepens the hole they are in and keeps him down,'' said David Gergen, a former White House aide to Presidents Richard Nixon, Ronald Reagan and Bill Clinton. ``It seems very unlikely he's going to get out of the hole, unless there's a miracle in Iraq.''

A Washington jury found Libby, Vice President Dick Cheney's former chief of staff, guilty of obstruction of justice and perjury during an investigation into who leaked the identity of a CIA official whose husband questioned the war.

Yesterday's verdict gives fresh ammunition to critics who charge Bush deceived Americans about the case for going to war, and comes at a time when the president is beset by a growing public backlash over the conflict, low approval ratings, and the threat of aggressive probes by Democrats in Congress into possible administration wrong-doing.

Bush ``has had to deal with Iraq, Katrina, and now a major scandal,'' Steven Schier, a presidential scholar at Carleton College, in Northfield, Minnesota, said in an interview.

Libby, 56, is likely to serve a prison sentence unless pardoned because the case ``goes to the very heart of the judicial process,'' said Robert Plotkin, a Washington defense attorney. Top congressional Democrats demanded that Bush promise not to pardon Libby, and said the case raises questions about Cheney's role.

`Deeper Truths'

``Lewis Libby has been convicted of perjury, but his trial revealed deeper truths about Vice President Cheney's role in this sordid affair,'' Senate Democratic Leader Harry Reid said in a statement.

The jury delivered its verdict as Congress began hearings on the ballooning controversy over whether the White House let politics interfere with the work of U.S. attorneys. One of eight U.S. attorneys Bush fired last year told Congress he was warned by a Justice Department official not to publicly criticize his dismissal and replacement by an aide to Karl Rove, Bush's top political adviser.

Libby was convicted of lying to FBI agents and a grand jury that investigated the leak of the identity of Valerie Plame, a covert Central Intelligence Agency expert on weapons proliferation.

Plame's Husband

Witnesses said the leak was part of a campaign by Cheney's office to undermine Plame's husband, a former diplomat who publicly questioned Bush's justification of the U.S.-led invasion of Iraq.

Testimony showed that Cheney was determined to discredit a New York Times column that Plame's husband, Joseph Wilson, wrote in July 2003. Wilson questioned Bush's assertion that Iraq was seeking enriched uranium for nuclear weapons.

``There is a cloud over what the vice president did,'' prosecutor Patrick Fitzgerald told jurors during his closing argument. ``That's not something we put there.''

Republican politicians, insisting on anonymity, said after the verdict that although the odds are very slim that Cheney might step down, that can't be totally dismissed. The vice president, polls show and politicians say, has become a serious political liability for the Bush administration.

Pardon Speculation

Bush spokeswoman Dana Perino last night called any speculation about a Cheney resignation ``absolutely ridiculous.'' White House press secretary Tony Snow said today that Cheney ``remains a trusted aide,'' someone ``upon whose counsel the president depends.'' Snow declined to comment on a possible pardon.

The verdict prompted immediate speculation about whether Bush would pardon Libby. Reid demanded the president ``pledge not to pardon Libby for his criminal conduct.''

Defense lawyers said Libby's attorneys probably will pursue ways to drag out legal proceedings. That strategy would push a presidential pardon decision beyond the 2008 election.

The court calendar will work in Libby's favor even if U.S. District Judge Reggie Walton sticks to the June 5 sentencing date, lawyers said. Because Libby isn't a risk to flee, he will likely remain free on bond pending appeal, lawyers said.

It takes 12 to 18 months from sentencing to get a decision on a criminal case from the U.S. Court of Appeals for the District of Columbia Circuit, said Barry Boss, a Washington defense lawyer. ``There is a good chance the appeal wouldn't be resolved much before the 2008 election,'' Boss said.

`Smear Critics'

The Libby case emboldened Bush's critics in the new Democratic-controlled Congress. House Speaker Nancy Pelosi said the trial ``unmistakably revealed -- at the highest levels of the Bush administration -- a callous disregard in handling sensitive national security information and a disposition to smear critics of the war in Iraq.''

The conviction may further weaken a president whose approval ratings have averaged a little above 30 percent in more than 10 recent public opinion polls. It will stay in the news for months because the Wilsons have filed a civil suit and Valerie Plame has written a book that the CIA is vetting.

``These problems tend to be cumulative,'' said Ross K. Baker, a political scientist at Rutgers University in New Brunswick, New Jersey. ``No single setback really causes the whole structure to collapse,'' Baker said. ``But it adds just one more point of weakness in the foundation of the Bush administration.''

`Uphold the Honor'

In his 2000 campaign appearances in Georgia, Colorado, and Michigan, Bush pledged to ``uphold the honor and the integrity of the office to which I have been elected, so help me God.'' That promise followed the 1998 impeachment by the U.S. House of Representatives of Clinton after revelations that he had an affair with a White House intern.

Presidential pardons are often controversial. Gerald Ford spared his predecessor Nixon from prosecution for Watergate crimes in 1974. The pardon was believed by political analysts to have cost Ford the 1976 election. Later he was largely vindicated and received a Profile in Courage award from the John F. Kennedy Library in Boston.

Bush's father, President George H.W. Bush, pardoned Caspar Weinberger in December 1992, two weeks before the former defense secretary was scheduled to stand trial on charges he lied about the Iran-Contra affair. Three former CIA officials involved in that scandal were also pardoned.

Clinton didn't pardon his former aide Webster Hubbell, who had been convicted in 1994 of embezzlement and served 18 months in prison. Clinton stirred a controversy on his last day in office in January 2001 by pardoning fugitive financier Marc Rich. One of Rich's lawyers at the time was Lewis Libby.

To contact the reporters on this story: Edwin Chen in Washington at Echen32@bloomberg.net; James Rowley in Washington at jrowley@bloomberg.net.

Last Updated: March 7, 2007 10:06 EST