BY RICHARD MORIN AND DANA MILBANK

WASHINGTON POST STAFF WRITERS

A majority of Americans believe President Bush either lied or deliberately exaggerated evidence that Iraq possessed weapons of mass destruction in order to justify war, according to a new Washington Post-ABC News poll.

The survey results, which also show declining support for the war in Iraq and for Bush’s leadership in general, indicate the public is increasingly questioning the president’s truthfulness — a concern for Bush’s political advisers as his reelection bid gets underway.

Barely half — 52 percent — now believe Bush is “honest and trustworthy,” down 7 percentage points since late October and his worst showing since the question was first asked, in March 1999. At his best, in the summer of 2002, Bush was viewed as honest by 71 percent. The survey found that nearly seven in 10 think Bush “honestly believed” Iraq had weapons of mass destruction. Even so, 54 percent thought Bush exaggerated or lied about prewar intelligence.

Honesty and credibility have been central to Bush’s appeal since the 2000 campaign, when he benefited from disgust over President Bill Clinton’s lies about the Monica S. Lewinsky affair and when Bush’s campaign accused then-Vice President Al Gore of “saying one thing and doing another.” But a number of factors, including the failure to find unconventional weapons in Iraq and the administration’s underestimating of its Medicare prescription drug plan’s costs, appear to have undermined perceptions of his credibility.

Bush’s possible Democratic opponent, Sen. John F. Kerry (Mass.), has begun to talk about a “credibility gap.” Even some Bush allies say they have been misled about Iraq’s weapons, and the current Time magazine cover story asks: “Believe him or not — does Bush have a credibility gap?”

Questions about Bush’s use of prewar intelligence, in addition to feeding doubts about his honesty, have sent his performance rating plummeting. Fifty percent of Americans approve of the job he is doing, the lowest level of his presidency in Post-ABC polling and down 8 percentage points from January. The survey found that, for the first time since the war ended, less than half of Americans — 48 percent — believe the war was worth fighting, down 8 points from last month. Fifty percent said the war was not worth it.

These doubts have affected Bush’s reelection prospects. In a head-to-head matchup, Kerry beat Bush, 52 percent to 43, percent among registered voters. Bush had more passionate support — 83 percent of his backers said their support was strong, while 59 percent of Kerry supporters said so — and retains an advantage over Kerry in dealing with Iraq and the war on terrorism. But the Democrat was seen as better able to handle the economy and jobs, education, and health care — all top issues with voters this year.

The survey found a steep drop in public perceptions of Bush as a president and as an individual. In a sign that Bush has been set back by recent controversies over Iraqi weapons, his National Guard record and the federal budget, the number of Americans viewing him as a “strong leader” has slipped to 61 percent, down 6 points from December and the lowest level since the 2001 terrorist attacks.

Bush’s rating on handling the economy stood at 44 percent, down 7 percentage points, with nearly half of the public saying they are worse off now than they were when Bush became president three years ago. Six in 10 disapprove of the job Bush is doing creating jobs. On education, 47 percent said they approve of the job Bush is doing, down 8 points from January. And his rating on health care has also fallen.

But the president’s declining ratings related to Iraq were the most striking. Approval of his handling of the situation there has fallen to 47 percent, down 8 percentage points in the past three weeks. About half of Americans — 51 percent — said they would prefer a report evaluating the accuracy and use of prewar intelligence before the election, while 35 percent favor what Bush has ordered: a broader study of the overall accuracy of U.S. intelligence-gathering operations that will report its findings after the election.

While 21 percent said they believe that Bush lied about the threat posed by Iraq, a larger number — 31 percent — thought he exaggerated but did not lie. Indeed, six in 10 Americans believed, as Bush did, that Iraq had such weapons.

Three in four Democrats said Bush either lied or exaggerated about what was known about Iraq’s weapons, while an equally large majority of Republicans said the president did neither. Slightly more than half of all independents believed Bush had misled the public about Iraq’s weapons cache.

“I think he was believing what he wanted to believe,” said one respondent, Ron Perholtz, an accountant from Jupiter, Fla. “I can’t say he’s dishonest. He heard what he wanted to hear. He’s manipulatable by [Vice President] Cheney and others.”

Many respondents expressed regrets about the Iraq war. For example, Mike Richcreek, 52, of Warner Robbins, Ga., said he believes Bush neither exaggerated nor lied. “He went by what the intelligence given to him showed,” Richcreek said. But, at the same time, Richcreek said he has begun to doubt the merits of the war.

“I’m not sure now we should have gone to war in the first place,” he said. “You think of all of our young kids getting killed. That’s a problem. I’m glad I didn’t have to make the decision.”

A total of 1,003 randomly selected adults were interviewed Feb. 10 to 11. The margin of sampling error for the overall results is plus or minus 3 percentage points.

Assistant polling director Claudia Deane contributed to this report.