A war-weary America may not embrace HBO's new mini-series on the early days of the invasion of Iraq

When it comes to depictions of the Iraq war, Hollywood is in the habit of throwing good money after bad. A spate of films based on the conflict has flopped at the box office: In the Valley of Elah, Rendition, Stop-Loss, Redacted, Lions for Lambs – none has grossed more than $15m in the US.

It's reasonable, therefore, to view HBO's new mini-series Generation Kill, which debuts in the US on Sunday night, with a dose of scepticism. Based on the bestselling book by journalist Evan Wright and produced by David Simon, creator of the hit series The Wire, the show follows a platoon of Marines as they lead the charge from Kuwait to Baghdad in the opening days of the war.

While the US commanders' lack of planning and foresight is well known by now, Wright documents the invasion not from Washington but from the backseat of a Humvee. His eyewitness account is gripping, absurd and heartbreaking.

That the Marines with whom Wright was embedded are all colourful characters - the "cowboys" of the Corps - certainly doesn't hurt. There's the stoic leader, Sergeant Colbert; the wisecracking Humvee driver, Corporal Person; the eager young gunner, Lance Corporal Trombley; the Zen master, Corporal Garza; and a host of others with nicknames like Encino Man and Captain America.

These young men are vulgar and juvenile, cynical and fatalistic. "Even though their Commander in Chief tells them they are fighting today in Iraq to protect American freedom, few would be shaken to discover that they might actually be leading a grab for oil," Wright says. "In a way, they almost expect to be lied to."

A Hollywood screenwriter would be hard-pressed to invent more engaging protagonists, and Simon wisely chose to reproduce Wright's account almost verbatim, using the book essentially as a script. Few screen adaptations are this good.

But will America watch? Critics of the war certainly hope so. As the Marines push north to Baghdad, the killing and maiming of innocent civilians becomes a dominant theme and one the HBO series does not shy away from. "We pass a bus, smashed and burned, with charred human remains sitting upright in some windows," writes Wright following an assault on the southern city of Nasiriyah. "There's a man in the road with no head and a dead little girl, too, about three or four [years old], lying on her back. She's wearing a dress and has no legs."

By the time the Marines reach Baghdad, they are both jaded and shaken. "Damn!" says one, surveying a by-now-familiar scene of carnage. "It looks almost half-civilised here." Another Marine has a different reaction. "Do you realise the shit we've done here, the people we've killed?" he asks Wright. "Can it get any sicker than this?"

The dismal track record of the earlier Iraq-themed movies suggests that Americans are more likely to ignore such depressing fare, rather than be spurred into action by it. "There is no war fatigue, there's war attention deficit disorder in this country," Wright observed at a preview screening hosted by Campus Progress. Simon, for his part, is sick of people asking whether anyone will tune in. "If they come, they come," he told the audience.

Yet the real reason Generation Kill will fail to jumpstart opposition to the war is that the events it documents are, in many ways, irrelevant to the current debate. The issue is no longer whether the invasion of Iraq was a just undertaking. To war supporters and critics alike, the decisions of the past five years have submerged that argument in an avalanche of foreseen and unforeseen consequences. Today, the debate is about whether and how we can withdraw our troops. It's a question, not about the war's first days, but about its final ones.