Ever since he began running for president, George W. Bush has told Americans that he is a "plain-spoken man," a leader who would never play games with words. "Whether you agree with me or not, you know where I stand," he said during his 2004 reelection campaign.
In a narrow sense, last week's disclosure of testimony that Bush authorized a leak of classified information to bolster his case for the war in Iraq poses a problem for the White House, because it appears to conflict with the president's promise to be a straight shooter.
More broadly, the leak controversy may be only a small part of a larger problem: a continuing erosion of public confidence in the president's credibility, especially on Iraq, which has become the defining issue of his presidency.
In public, the White House and the Republican National Committee dismissed the controversy as a partisan sideshow. Bush doesn't have a credibility problem, spokesman Scott McClellan said; "the Democrats have a credibility problem when they try to suggest that we were manipulating intelligence." But independent pollsters and political scientists -- as well as some Republican strategists -- disagree.
"This kind of story hits at one of the president's few remaining strengths, the perception that he is principled," said Christopher Gelpi of Duke University, who has generally been sympathetic to the White House. "The president's credibility on Iraq is already low outside the Republican Party, and this digs the hole deeper."
Said Republican pollster Tony Fabrizio: "This isn't good. When your image is being battered on a host of other issues, the one thing you don't need is a question of veracity."
However, he added: "Let's not exaggerate the importance of this.... By no stretch of the imagination is this Nixon-esque."
Congressional Republicans declined to comment, even as Democratic leaders seized the opportunity to condemn the president and demand an investigation. "It's certainly not good," an aide to a leading Republican senator said, speaking on condition of anonymity because he was not authorized to talk on the record. "But we want to see how it settles out."
Some Republicans predicted that the issue would go nowhere. "This needs to play out over the next seven days," said Joseph E. diGenova, a federal prosecutor under President Reagan. "This is just inside-the-Beltway stuff. If Republicans stick with [Bush], it will become a partisan issue and people will turn it off."
But others were more worried. "For the first time, this issue has been taken right into ... the Oval Office," said a senior GOP figure, who spoke on condition of anonymity to avoid harming his relationship with the White House. "That's not a small step. It's a huge step."
Last week's controversy was touched off by a court document filed by a special prosecutor seeking a perjury conviction against I. Lewis "Scooter" Libby, Vice President Dick Cheney's former chief of staff.
According to the prosecutor, Libby has testified that he gave classified information about U.S. intelligence on Iraq to New York Times reporter Judith Miller in 2003 after Cheney told him that Bush had personally approved the secret disclosure.
Libby's leak apparently was intended to encourage Miller to write an article saying that U.S. intelligence agencies genuinely believed that the Iraqi regime of Saddam Hussein had sought nuclear weapons.
At the time, the White House was trying to rebut charges from former Ambassador Joseph C. Wilson IV that the administration had exaggerated Iraq's nuclear programs. During the same period, it was disclosed that Wilson's wife, Valerie Plame, was a CIA officer.
The potentially criminal disclosure of Plame's identity launched the investigation that led to Libby's indictment on perjury charges.
Bush denounced that leak along with other disclosures of secret information. "If somebody did leak classified information, I'd like to know it, and we'll take the appropriate action," he said in September 2003.
Last week, White House spokesman McClellan refused to comment directly on the case and did not deny that Bush authorized Libby to pass previously classified information to the New York Times reporter.
But McClellan offered a broad defense on Bush's behalf. He suggested that if the president authorized a secret disclosure of intelligence information, it should not be considered a leak because the president has the power to declassify, and because any such action he took would be "in the national interest."
Whether or not that argument proves convincing, and whether or not the public pays close attention to the legal tangles, Bush faces a deeper problem that has bedeviled many of his predecessors: When a president's credibility wanes, a succession of small incidents can pile into something more significant.
"There's a spillover effect," said Gelpi, who has focused on public opinion in wartime. "The public reaction to Hurricane Katrina
Public opinion polls show that a majority of the public considered Bush honest in his statements about Iraq until 2004, when his credibility was shaken by bad news from the battlefield and the fact that Hussein was never found to have weapons of mass destruction, which contradicted the administration's principal argument for war.
The public's view of Bush's overall honesty has slipped further in recent months, in the wake of the government's confused response to Katrina, the Libby investigation and other setbacks.
In a Los Angeles Times poll in November 2003, 56% of respondents said they considered Bush "honest and trustworthy." When the same question was posed in January 2006, 46% answered that way.
Similarly, in an Associated Press-Ipsos poll in October 2004, 53% of respondents said Bush was honest; in a poll taken in March and released last week, 44% called him honest. (In the latter poll, 59% did say the president is "likable.")
Bush is not the only president who has faced such challenges.
Lyndon B. Johnson lost credibility during the Vietnam War and declined to seek a second full term. The Watergate scandal so eroded Richard Nixon's credibility that he resigned.
Ronald Reagan suffered a precipitous drop in credibility when it was revealed that he had secretly authorized weapons sales to Iran, but he recovered his public standing by the end of his second term. Bill Clinton lost much of his credibility in a 1998 sex scandal, though he was forgiven by much of the electorate.
But Bush has at least one problem that Reagan and Clinton did not: A major source of his credibility problem is his most important foreign policy initiative, the war in Iraq, and his ability to affect the war's course is limited.
"If the issue were Social Security or the budget, you could change the way you talked about it," Fabrizio, the GOP pollster, said. "The problem is that the issue that has become the centerpiece [of Bush's presidency] is beyond their control. The first rule of crisis management is, when you're in a hole, stop digging. But the White House isn't holding the shovel, and the hole is being dug for them."
Moreover, DiGenova said, the White House has dismissed questions stemming from the special prosecutor's investigation with the explanation that it can't comment on an ongoing legal case. "They're not coming to their own defense," he said.
With Bush's overall standing at a low and with a congressional election campaign ahead, Republicans are bracing for a difficult year. "We're in a tough environment," Fabrizio said. "And if more information comes out [in the Libby case], it could be even tougher."
The special prosecutor signaled in his court filing last week that he intended to call several former Bush aides as witnesses against Libby, including former Secretary of State Colin L. Powell and former White House Press Secretary Ari Fleischer -- raising the specter of court proceedings that could lay bare the inner workings of the White House.
"I can't imagine this case going to trial," DiGenova said. "You'll see a pardon first."
The White House has refused to say whether Bush might pardon Libby, citing its policy of not commenting on the case.