Americans believe in evil, but we're uncomfortable with tragedy. We accept that there are wicked people in the world, with malice in their hearts and a devil whispering in their ears. But the idea that many debacles flow from choices made by decent, well-intentioned human beings is more difficult for us to wrap our minds around. This is apparent in our politics, where we're swift to impute the worst of motives to anyone slightly to our left or right. It's apparent in our popular culture, thick with white hats and black hats, superheroes and supervillains. But it's most egregious where the two spheres intersect: in our political fictions, which are nearly always Manichaean, simplistic and naive. Consider 'Green Zone,' the new Matt Damon thriller that doubles as a meditation on Why We Are in Iraq. The director is Paul Greengrass, a talented Englishman whose quease-inducing 'United 93' remains one of the few compelling films to emerge from 9/11. The source material is Rajiv Chandrasekaran's 'Imperial Life in the Emerald City,' a dense and nuanced account of the Iraq occupation's disastrous first year. But the film itself, a slam-bang account of the hunt for weapons of mass destruction, has the same problem as nearly every other Hollywood gloss on recent political events: it refuses to stare real tragedy in the face, preferring the comforts of a 'Bush lied, people died' reductionism. The narrative of the Iraq invasion, properly told, resembles a story out of Shakespeare. You had a nation reeling from a terrorist attack and hungry for a response that would be righteous, bold and comprehensive. You had an inexperienced president trying to tackle a problem that his predecessors (one of them his own father) had left to fester since the first Gulf War. You had a cause -- the removal of a brutal dictator, and the spread of democracy to the Arab world -- that inspired a swath of the liberal intelligentsia to play George Orwell and embrace the case for war. You had a casus belli -- those weapons of mass destruction -- that even many of the invasion's opponents believed to be a real danger to world peace. And you had Saddam Hussein himself, the dictator in his labyrinth, apparently convinced that pretending to have WMD was the best way to keep his grip on power. But this opening act, and all the tragedies that followed, still awaits an artist capable of wrestling with its complexities. In 'Green Zone,' everything is much simpler. 'We' were lied to. 'They' did the lying. The 'we' is the audience, Matt Damon's stoic soldier and the perpetually innocent American public. The 'they' is the neoconservatives, embodied by a weaselly Greg Kinnear (playing some combination of Donald Rumsfeld, Paul Bremer and Douglas Feith) and capable of any enormity in the pursuit of their objectives. Such glib scapegoating looks particularly lame in the wake of last week's Oscar triumph for 'The Hurt Locker,' the first major movie to paint the Iraq War in shades of gray. But 'The Hurt Locker,' of course, was largely apolitical. Throw politics into the mix, and there seems to be no escaping the cliches and simplifications that mar Greengrass' movie -- and Robert Redford's 'Lions for Lambs,' Oliver Stone's 'W.' and all the other attempts to bring the Bush era to cinematic life. This isn't just a Hollywood problem. Explaining 'Why Americans Can't Write Political Fiction' in a 2005 essay for the Washington Monthly, Chris Lehmann noted the long-running tendency in American letters to depict politics as the preserve of debased cynics and moral monsters. From Mark Twain's 'Gilded Age' and Robert Penn Warren's 'All the King's Men' to their more recent imitators, our novelists have never been terribly interested in the actual challenges of political life. Instead, Lehmann suggested, they usually cast the entire mess as 'a great ethical contaminant and task their protagonists with escaping its many perils with both their lives and their moral compasses intact.' As it happens, this is a pretty good description of the arc of 'Green Zone.' But it's a lousy recipe for real art, which is supposed to be interested in the humanity of all its subjects, not just the ones who didn't work for Rumsfeld's Department of Defense. Such radical sympathy, extended even to people who presided over grave disasters, is in short supply all across America at the moment. And Hollywood's inability to handle political complexity plays only a small part in our ongoing polarization. But it is a part of it. Our nation might be less divided, and our debates less poisonous, if more artists were capable of showing us the ironies, ambiguities and tragedies inherent in our politics -- rather than comforting us with portraits of a world divided cleanly into good and evil. 