Were I to say that Paul Greengrass's Green Zone is the best movie yet made about the Iraq War, virtually nobody would agree with me, and I'm okay with that. But it's much harder to disagree that it's probably the most outraged movie about Iraq (Kimberly Pierce's Stop-Loss is the other candidate), and if I'm showing my ideology by saying that "best" and "most outraged" aren't readily separable, then so be it.

I call it Greengrass's film, even though without screenwriter Brian Helgeland and star Matt Damon, it would be a different and assuredly lesser movie, because the line connecting it to his previous work is clear and unmistakable. The director's four features in the '00s divide cleanly into two camps: a pair of historical docudramas, and a pair of action thrillers with an aggressive style of frenzied handheld camera and quick editing. Green Zone combines these two camps more or less equally: as a docudrama, it is not a strict fact-based story, although most of the characters are clearly based on real-life individuals, and it in essence tells how the Iraq mire got started (it is not"based on" Rajiv Chandrasekaran's 2006 non-fiction book Imperial Life in the Emerald City, but that book is a primary text); as a thriller, it uses virtually the same style that was perfected in The Bourne Ultimatum, though it is not so over-the-top, perhaps.

Of the director's last four movies, only 2002's Bloody Sunday has an obvious, one-sided political message to make, as does Green Zone. There is no doubt that Greengrass and Helgeland believe that the United States government either lied to its citizenry, or was willingly misled by clearly false intelligence that Saddam Hussein's government was actively developing weapons of mass destruction, and that it is either way an evil thing to have happened. The immediate response made by the film's surprisingly robust contingent of detractors is that it's 2010 now, and getting morally indignant about the war isn't really the point; this is a debate seven years old now, and we should move on to other, more immediate concerns. It remains the case, however, that mainstream American culture has been pretty eager to gloss over the details of how the war was started in March, 2003, moving from "maybe they did have WMDs" to "clearly, they had no WMDs, but that doesn't matter now that we're at war" very, very quickly; one assumes (if one is an agitated leftist filmblogger) that this is due to mainstream culture's deserved embarrassment at having handed the Bush administration a free pass to do whatever the hell it wanted to in the run-up to war. Greengrass and Helgeland will have none of that, and their film is an angry reminder of exactly how easily we the people (in the form of Damon's Chief Warrant Officer Roy Miller) were duped by people who weren't even very good liars. That process hasn't been given a thorough treatment in a narrative film yet - last year's In the Loop came closest - and while I'll concede that Green Zone would have "meant more" if the director had made it when he first thought of making an Iraq picture, before The Bourne Ultimatum in 2007, that's hardly to say that it doesn't have any value today. Those who forget history are doomed to something or other.

At the same time, Green Zone isn't at all a filmed editorial, like the catatonic Lions for Lambs; Greengrass has made quite a raucous, energetic action movie to serve as the vehicle for his polemic. The specific nature of that energy is the notorious shaky camera and whiplash editing of The Bourne Ultimatum, an aesthetic that has lost much of its street cred in just two and a half short years; the diplomatic thing would be to say that it's "divisive", with people either decrying it as incoherent and nauseating, or adoring it as the second coming of action filmmaking. I'm firmly in the second group; for all that I hate handheld camera most of the time, I found Ultimatum to be the most exciting and revolutionary step in action filmmaking since probably the 1970s, at least as far as Greengrass and his collaborators execute it (like that film, Green Zone was edited by Christopher Rouse; it was shot by Barry Ackroyd, who has suddenly become the golden child of kinetic Iraq movies, having just been Oscar-nominated for shooting The Hurt Locker). In their hands, this is the aesthetic of chaos and confusion and endless movement; if you stop, then you die.

Politics aside, Green Zone is one hell of a war movie, if you're okay with Greengrass's balls-out style. The first major action sequence, Miller's team raiding what turns out to be an abandoned toilet factory, is probably the most effective ground combat scene since Black Hawk Down,* a hell of light and dark and the shrieking noise of machines and bullets. For that matter, the final sequence is pretty damn good itself, with the editing reaching such a fevered pitch that I was quite literally breathless by the time it slowed down. And between these points, it's an outstanding paranoia-type thriller about Miller's accidental investigation into who knows what about the bad intelligence that leads his team from one false WMD to another, even though we pretty much know from the beginning exactly how it has to end. There is a bit of a sag in the second quarter of the film, when all of the pieces are being set up in a series of oddly talky scenes, but once that necessary exposition is out of the way, it's back to noise and tension and the sight of cinema tearing its own guts out on that merciless aesthetic.

Besides the sag in the first half, there are a few other missteps: John Powell's score is obvious and cloying and far too present, and the last 90 seconds, maybe less, are not at all in keeping with the direction the story has gone before then (and nothing but nothing is more irritating than a misjudged ending). Some might also suggest the frequently on-the-nose dialogue is a problem, but I rather like the way that Greengrass uses it: he needs obvious thematic statements and simple characterisations to make the point of the film clear while he blitzes through the plot with his sound and fury. This is not, by any stretch of the imagination, a human story - though Damon's natural state as an everyday regular fella, to use Steven Spielberg's old phrase, makes Miller a rather perfect tabula rasa as the Average American who really did trust Bush on the WMD issue - which will curry the film no favors in an environment in which The Hurt Locker just won a truckload of Oscars precisely because it is a human story in Iraq. No, Green Zone is a very broadly social story, telling of the movement of government and factions as embodied by people who are otherwise given little definition beyond "Craven D.C. bureaucrat", "embittered Iraqi general", and so on. That, plus the politics, plus the unforgiving stylistic craziness, is going to leave plenty of people unhappy with the film, but I have to be honest about my own response: as a left-wing formalist, I loved it more than any war movie I've seen in years.