Approval of Bush's handling of Iraq, which has been hovering in the low, to mid-40s most of the year, dipped to 38%.
Those living in the Midwest and young men and women with a high school education or less were most likely to abandon Bush on his handling of Iraq in the last six months.
William Anderson, a retired Republican from Fort Worth, Texas, said Bush "has the right intentions, but he's going about them the wrong way."
"Iraq is one of the issues that everybody has a problem with," Anderson said.
"There are some big discussions about it around town. Everybody's got their agreements and disagreements. It seems like there's no end. Is it going to end up another Vietnam?"
"Iraq is one of the issues that everybody has a problem with"
William Andersosn, a retired Republican
Continuing worries about Iraq may do more than drag down Bush's standing with the public. They could become a major issue in the 2006 mid-term congressional race, and if the war is still going on in 2008, they could be a factor in the presidential race.
American troops have suffered heavy casualties in Iraq in recent days. On Wednesday, 14 Marines were killed in the Euphrates River valley, in the worst roadside bombing targeting Americans since the war began in March 2003.
The portion of people who consider Bush honest has dropped slightly from January, when 53% described him that way while 45% did not. Now, people are just about evenly split on that issue, with 48% saying he is honest and 50% saying he is not.
Yet, a solid majority still see Bush as a strong and likable leader, though the president's confidence is seen as arrogance by a growing number.
US troops have suffered heavy
casualties in iraq in recent days
Almost two-thirds in the poll described Bush as strong and likable.
But the portion of people who view his confidence as arrogance has increased from 49% in January to 56% now.
Bush's overall job approval was at 42%, with 55% disapproving. That is about where Bush's approval has been all summer, but slightly lower than at the beginning of the year.
Six in 10 said they thought the country was headed down the wrong track, despite some encouraging economic news in recent weeks.
The poll of 1000 adults was conducted on 1-3 August by Ipsos, an international polling firm.
It has a margin of sampling error of plus or minus 3 percentage points.