Washington ? A third of the American public believes U.S. forces found weapons of mass destruction in Iraq, according to a recent poll. And 22 percent said Iraq actually used chemical or biological weapons.

Before the war, half of those polled in a survey said Iraqis were among the 19 hijackers on Sept. 11, 2001.

But such weapons have not been found in Iraq, and were never used. Most of the Sept. 11 hijackers were from Saudi Arabia. None were Iraqis.

How could so many people be so wrong about life-and-death information that has dominated news coverage for almost two years?

These poll results startled the pollsters who conducted and analyzed the surveys.

“It’s a striking finding,” said Steve Kull, director of the Program on International Policy Attitudes at the University of Maryland, which asked the weapons questions during a May 14-18 poll of 1,256 respondents.

He added, “Given the intensive news coverage and high levels of public attention, this level of misinformation suggests some Americans may be avoiding having an experience of cognitive dissonance.”

That is, having their beliefs conflict with the facts.

Kull added that the poll’s data showed that the mistaken belief that weapons of mass destruction had been found “is substantially greater among those who favored the war.”

Pollsters and political analysts see several reasons for the gaps between facts and beliefs: the public’s short attention span on foreign news, fragmentary or conflicting media reports that lacked depth or skepticism, and White House efforts to sell war by oversimplifying the threat.

“Most people get little whiffs and fragments of news, not in any organized way,” said Thomas Mann, a scholar at the Brookings Institution, a centrist-liberal think tank. “And there have been a lot of conflicting reports on the weapons.”

Before the war, the U.S. media often reported as fact the assertions by the Bush administration that Iraq possessed large stockpiles of illegal weapons. CBS News in December reported how Bush officials were “threatening war against Iraq and its weapons of mass destruction.”

During and after the war, reports of weapons discoveries were often trumpeted on front pages, while follow-up stories debunking the “smoking gun” reports received less attention.

“There were so many reports and claims before the war, it was easy to be confused,” said Larry Hugick, chairman of Princeton Survey Research Associates. “But people expected the worst from (Iraqi President) Saddam Hussein and made connections based on the administration’s policy.”

Bush has described the pre-emptive attack on Iraq as “one victory in the war on terror that began Sept. 11.” Bush officials also claim that Iraq sheltered and helped al-Qaida operatives.

“The public is susceptible to manipulation, and if they hear officials saying there is a strong connection between Iraq and al-Qaida terrorists, then they think there must be a connection,” Mann said.

“Tapping into the feelings and fears after Sept. 11 is a way to sell a policy,” he added.

While Bush critics see an effort to mislead the public, some analysts say Bush has been following a long presidential history of framing a foreign crisis for maximum domestic benefit.

“I’m not going to defend the president, but a policy of pre-emptive attacks sure looks better after this country has been hit hard,” said Sam Popkin, a polling expert at the University of California at San Diego who has advised Democratic candidates.

Polls show strong support for Bush and the war, although 40 percent in the May survey found U.S. officials were “misleading” in some of their justifications for war. A majority, 55 percent, said they were not misleading.

“People supported the war for national security reasons and that shifted to humanitarian reasons when they saw evidence of Saddam’s atrocities,” said Republican strategist Frank Luntz. “There’s an assumption these weapons will be found because this guy was doing so many bad things.”

Several analysts said they are troubled by the lack of knowledge about the Sept. 11 hijackers, shown in the January survey conducted for Knight Ridder papers.

Only 17 percent correctly said that none of the hijackers were Iraqi.

“That really bothers me because it shows a lack of understanding about other countries . . . that maybe many Americans don’t know one Arab from another,” Popkin said.

The survey for Knight Ridder by Princeton Survey Research Associates questioned 1,204 American adults between Jan. 3 and 6 and has a margin of error of plus or minus three percentage points.

Hugick said his analysis shows those who are misinformed are not necessarily those who have less education.

“I think a lot of people are just confused about the threats out there,” he said.