Film-makers have still not worked out a way to process the wars in Afghanistan and Iraq into fiction. I admired parts of Rendition, but even that is a doodle on a Post-it note next to the Goya-like tableaux conjured up by the documentary Taxi to the Dark Side. In 2002, a 22-year-old taxi driver known as Dilawar was turned over to US interrogators at the Bagram Air Base by Afghan militiamen who claimed he had been launching rocket attacks on Allied forces. Five days of American hospitality, and Dilawar was dead. Alex Gibney's Oscar-winning film collects the testimonies of those present at Bagram, including Damien Corsetti, an interrogator with a neck the size of a small continent. A brass neck, at that. Here is his angle on Dilawar: "They're a very frail people. It surprised me that it had taken so long for one of them to die in our custody."
You take the point. What kind of namby-pamby race expires after barely a week of savage beatings, torture, sleep deprivation, enforced standing and tissue damage? (Had Dilawar lived, the coroner observed, his "pulpified" legs would have had to come off.) Colonel David Hayden is an army lawyer who went to the same charm school as Corsetti. "This is not a hotel," he says. "This is not a place for [detainees] to get fat, lazy and happy." Gibney cuts to Dilawar naked on the mortuary slab. He has bruises in colours you never knew existed.
This story might have been enough on its own for a whole film. Just when you think you've heard it all, you hit yet another pothole of grief or outrage, such as when the New York Times reporter Carlotta Gall tracks down Dilawar's family members, and they produce a note that came attached to his body. It's the death certificate, with a tick in the box marked "homicide", and Gall has to explain to them what this means.
But what makes Taxi to the Dark Side an important film, rather than just a compelling one, is Gibney's ability to situate Dilawar's death in the context of the relationship between the White House and the grunts on the ground, who escaped charges of dereliction of duty because no one ever clarified what their duty was. With no advice on where to draw the line, they found it became all too easy to cross it instead. One soldier, who joined in the general pummelling of prisoners at Bagram, is defensive: "I didn't wanna appear to be going against my fellow soldiers. Is that wrong?" Well, if you have to ask . . .
The film sends out feelers in all directions - to Donald O Hebb, whose research into sensory deprivation in the late 1950s and early 1960s gave the CIA a new box of tricks to play with; to Guantanamo Bay and Abu Ghraib, where "the Bagram model" really caught fire; to John Yoo and Alberto Gonzales, paid to find ways around the Geneva Conventions; and to the torture-porn of the appalling 24, which sets out to corrode its audience's opposition to human rights abuse.
For all the physical violence on show, this is partly a story about semantics. George W Bush's declaration that "we do not condone torture" is perfectly true, once you accept that he is using his own eccentric definition of torture. (It does not include the medieval practice of waterboarding, described here by Dick Cheney as "a dunk in water", like baptism or bobbing for apples.) The film keeps touching on those ways in which acronyms, words and the spaces between them are used to obscure or ratify brutality. Even now it gives me a jolt to hear about "extraordinary rendition", which could still refer to an audacious cover version or poetry recital.
If some of Taxi to the Dark Side feels familiar, perhaps it's just that we've become accustomed to the constant low hum of horror: if we didn't steel ourselves for the worst, the shock would be unmanageable. The film's expertise lies in its intelligent arrangement of material, and the way Gibney keeps pulling back from the Dilawar case to show its precedents and repercussions. Oh - and Dilawar was innocent, in case you were wondering. His interrogators knew that, even as they were cooking up ingenious ways to prolong his suffering.
Pick of the week
California Dreamin’ (Endless) (15)
dir: Cristian Nemescu
The US army is stuck in rustic Romania. Hilarity ensues. No, really.
In Search of a Midnight Kiss (15)
dir: Alex Holdridge
Low-budget, LA-set comedy romance.
The Incredible Hulk (12A)dir: Louis Leterrier
Back to the drawing board after the unloved 2003 Hulk.