REALITY: Before discussing the themes and political ideas of the film I should first address the film itself, as a piece of entertainment. Green Zone had my complete attention from start to finish. I didn't completely see any major plot points coming, the action scenes were intense, and Matt Damon plays a totally convincing hero that you want to stand behind.
Damon plays Miller, a soldier in Iraq searching sites for weapons of mass destruction. Miller and his team continually find nothing so Miller begins to question where the intelligence is coming from, and thus begins his quest. All authority figures motives and actions are questioned and Miller has to make some tough decisions, but his motives are always on the side of what is 'right' and towards ends which he feels will cause less casualties. As the film progresses, these admirable and heroic motives are problematised. I think the "moral" or theme of the film is summed up best by Freddy, an Iraqi character: "It is not for you to decide what happens here".
The politics of the film are fairly obvious from the outset. The American government is not shown in a very flattering light, while soldiers such as Miller are shown to be good hearted people who are trying to do what is right and help people. The screenplay is based on the novel Imperial Life in the Emerald City: Inside Iraq's Green Zone by Rajiv Chandrasekaran, an Indian-American journalist. I'm unsure of how much the screenplay strays from the facts of the novel, but I think the knowledge that there were no WMDs in Iraq is fairly commonplace now. What may not be commonplace is the reasons why soldiers were sent to search for WMDs in the first place. Director Paul Greengrass places the viewer pretty firmly behind Miller as he uncovers the truth behind what is happening, and showing us these "truths" through the eyes of a heroic soldier is extremely effective. I think it's also a pretty ballsy move, considering there are still foreign soldiers in Iraq as this film is released.
Even if you find the politics of the film too straight forward or too boring or you disagree with them completely, I think that Green Zone is a solid spy/action/war/whatever you want to call it film and a totally enjoyable gripping watch.