One such group, Freedom's Watch, which has ties to the White House, ran television ads in the Philadelphia market and others around the sixth anniversary of the attack — when Gen. David H. Petraeus was also delivering his report to Congress on the progress of the war — suggesting a connection between the war in Iraq and the terrorist attacks.

One of the ads features Laura Youngblood, 28, from Sebastian, Fla. Mrs. Youngblood’s uncle was a New York City firefighter killed on 9/11 and her husband was killed in Iraq. The ad opens with photos of the two men. Mrs. Youngblood is heard saying, “I lost two family members to Al Qaeda, my uncle a fireman on 9/11 and my husband Travis in Iraq.” Mrs. Youngblood’s own story includes a tour of duty as a Marine Corps medic. Her husband Travis was also a Marine Corps medic and volunteered to go to Iraq while on shore duty in Illinois. “He said the terrorists have to be stopped and he would be one of the last men standing to make sure his family and his country were safe,” Mrs. Youngblood said in an interview. “We’re not in Iraq to fight Iraq, we’re in Iraq to defeat terrorism.”

One of the most striking poll findings is the number of people who continue to think Saddam Hussein was behind the Sept. 11 attacks. Depending on how it is asked, more than a third of Americans say Saddam Hussein was personally involved in those attacks. In a New York Times/CBS News Poll in September, 33 percent of the respondents said Saddam Hussein was “personally” involved. In June, when Princeton Survey Research, polling for Newsweek, asked if “Saddam Hussein’s regime was directly involved in planning, financing or carrying out the terrorist attacks,” 41 percent said yes.

There was a time, though, when a majority of Americans thought Saddam Hussein was involved in 9/11. In a Times/CBS News poll in April 2003, just after the war began, 53 percent of Americans said Saddam Hussein was personally involved. That wide perception didn’t last. By September of that year, 43 percent said Saddam Hussein was involved.

The respondents in the Times/CBS News poll last month who said Saddam Hussein was personally involved in 9/11 were more likely to say getting involved in Iraq was the right thing to do — 59 percent compared with 31 percent. These respondents were also more likely to see Iran as an immediate threat that cannot be contained.