Columbus, Ohio: For the people of Ohio, in America's industrial heartland, mention of Haditha still stirs up feelings of pride in the noble sacrifice of its Lima Company, a group of marine reservists who suffered the highest casualty rate in Iraq.

But with the scandal surrounding alleged war crimes by Lima's successor unit growing by the day, relatives of Ohio's dead now fear that "Haditha" could become a byword for national shame, and eclipse the heroism of their loved ones.

"The mere fact that it's Haditha will reflect on Lima Company," said Bob Derga, whose son, Cpl Dustin Derga, 24, was killed by an armour-piercing bullet in May, 2005. "It's going to tarnish a lot of the accomplishments."

In seven months in Haditha, in western Iraq, Lima Company's 184 marines suffered 23 killed in action and 36 wounded.

Their experience, immortalised in a recent and harrowing two-hour television documentary, using jerky amateur footage taken by the Marines themselves, has been seared on the American consciousness.

"It made it more personal because it was no longer just statistics or a name flashed on a television screen,'' said Derga. "It was people from their communities, not career Marines college kids, school teachers, policemen, firemen. All of a sudden, the war became real."

One young Marine, later killed, is shown eating 15 pizzas, to his comrades' mirth. His friend, also now dead, strums the guitar and sings Puff the Magic Dragon. Yet another wishes his daughter, whom he will never see again, a happy sixth birthday.

When 14 from Lima died in a roadside bomb blast last August, just two days after six Ohio-based snipers attached to the unit had been killed, backing for the war in the rust-belt state was shaken.

"Until then, Middle America was supporting the war," said Paul Schroeder, whose son, L/Cpl Edward "Augie" Schroeder, 23, was one of the 14 killed. "All of a sudden you had lifelong Republicans, Bush supporters, starting to question things. It was the tipping point when people started to go the other way. America woke up."

When the remnants of Lima Company returned to its Columbus headquarters last October, however, more than 30,000 Ohioans gave them a tumultuous welcome. "They were a very special group of Marines, and that's not just post-mortem glorification," said Carole Hoffman, whose son, Sgt Justin Hoffman, 27, was killed. "Our community really rallied together."

President George W. Bush was re-elected to the White House in 2004 on the strength of a narrow victory in Ohio. Since then, his popularity has plummeted in the state. A University of Cincinnati poll last week gave him a 35 per cent approval rating, the lowest in Ohio for any president in 25 years.

With the military death toll in Iraq creeping inexorably towards 2,500, Bush's advisers fear that the Haditha incident, in which Marines from Kilo Company are accused of shooting 24 innocent people, could fatally undermine his presidency.

Derga, 51, is a strong supporter of the Iraq war who became a leading member of Ohio Families United after his son was killed. Schroeder, 57, founded an anti-war group, Families of the Fallen for Change, that boasts 1,200 members.

Both are united in grief - last week they hugged each other at a private showing of the film but also in their belief that battle stress was a significant factor in the actions of the accused Marines. "I'm not surprised,'' said Schroeder. "They don't know who they can trust. My son said that somebody who's smiling at you in the day can be shooting you at night, or vice versa. Add to that exhaustion and an atmosphere in which you are taught to hate the enemy. Hate gets in the way. That's the tragedy of war."

The Telegraph Group Limited, London 2006

Is US resolve wavering in Iraq?

London: Struggling to control his emotions in an interview for the film, Combat Diary, Sgt Guy Zierk described how he had almost gone beserk and killed two women and a boy cowering in a house.

"I'm so close to shooting them but I don't," he said as he relived the moment. It'd make me no better than the people we were trying to fight over there."

Bob Derga fears that US resolve might be wavering. "This war will be won not on the battleground of Iraq but in the hearts and minds of American people."

But Paul Schroeder advocates withdrawal and believes Americans can now dissent from the troops' Iraq mission without being accused of being unpatriotic.