It is not a problem that "Green Zone" provides a fictional explanation for why Iraq was initially invaded in March 2003 under the false pretense that the country was hiding weapons of mass destruction—Quentin Tarantino, after all, wildly rewrote history with 2009's invigorating "Inglourious Basterds"—but it is a problem just how languid and stringently orthodox the storytelling is. Director Paul Greengrass, responsible for the last two exciting "Bourne" movies (2004's "The Bourne Supremacy" and 2007's "The Bourne Ultimatum") and 2006's stunning "United 93," is fast becoming a cliché of himself. Adopting intentionally messy hand-held camerawork and erratic, jittery editing, Greengrass' style proves beyond tedious here, not helped by the narrative's lack of substance outside of some unsubtle, decidedly pointed political leanings and the decision to do away with all character development. Without pacing momentum or a human connection to latch onto, the film becomes a one-note chore to sit through.

Four weeks following the U.S. raid on Baghdad, Chief Warrant Officer Roy Miller (Matt Damon) suspects the government may be sending out wrong information to him and his men after three consecutive sites purported to be holding WMDs turn up empty. CIA agent Martin Brown (Brendan Gleeson) confirms that something definitely fishy is going on and urges him to find out what it is. As Miller digs deeper, his investigation ultimately leads him to slippery Defense Intelligence agent Clark Poundstone (Greg Kinnear), who knows more than he's feigning; tireless newspaper journalist Lawrie Dayne (Amy Ryan); and the identity of the mysterious confidential Intel source known only as "Magellan."

"Green Zone" dresses the part of a mature-minded war drama for adult audiences, but it is every bit as by-the-numbers as that particular genre will allow. The people on hand are all types, none of them written with insight or depth: there's the heroic military officer who risks his life to find the truth, the shady government official, the plucky female reporter, the questioning CIA agent, and so on and so forth. These characters are stripped of pasts, backgrounds, or lives outside of what plays out on the screen, a screenwriting decision courtesy of Brian Helgeland (2009's "Cirque du Freak: The Vampire's Assistant") that is not only lazy, but also intensely frustrating. That, by the way, is the only thing intense about a film that has chases, firepower and shootouts to spare, but no ability to cohesively build suspense or a proper catharsis.

Matt Damon (2009's "Invictus") is acceptable as Officer Roy Miller, but the part—seemingly tailor-made for him—offers him little to do but run around with a gun, instruct the men under him, and question authority figures. A great range is not called for; Damon says his all-business lines with conviction and that's as far as he is able to go. Amy Ryan (2007's "Gone Baby Gone") tries to breathe some form of vitality into her thankless role as Lawrie Dayne, but it is all in vain. Brendan Gleeson (2008's "In Bruges") is just as squandered as CIA operative Martin Brown, while Greg Kinnear (2008's "Flash of Genius") does well appearing affable and crooked at the same time as Clark Poundstone. Since the main cast members make so little impression, it's safe to say the rest of them are virtual non-entities.

Near the end of "Green Zone," following one of those clunky climaxes where the protagonist's life is spared by an overly talkative bad guy and troops swooping in to rescue him, Roy Miller confronts Poundstone with an article he's written exposing the dirty truth behind the Iraq invasion. When he is told not to concern himself with such matters, Miller shouts at him, "The reasons we go to war always matter." It's a valid statement, and, in their own way, the details behind the government's deceptions seem potentially plausible. Knowing that they aren't, however, strips the picture of its purpose and makes the third act a bit too sanctimonious for its own good. It also comes too late to save a film that has both bored and spun its wheels for the last 100 minutes. Stacked next to far better similar films like 2007's "In the Valley of Elah" and 2009's "The Hurt Locker," "Green Zone" is shrug-worthy small potatoes destined to be quickly forgotten and replaced.