Green Zone: R: violence, language; 1:55; $ $ $ (out of $5)

Action star Matt Damon is his intense best, director Paul Greengrass shakes the hell out of his alleged Steadicam, and the folks on foreign soil legitimately despise American intervention.

Sound like one of the Greengrass/Damon “Bourne” movies? Guess again. This one is called “Green Zone,” a war movie with a message we’ve heard before (even if it might be worth repeating): The U.S. — and particularly the Bush (Jr.) administration — screwed up big time by sending troops to Iraq looking for weapons of mass destruction, now and forever known as WMDs.

Finding them is Damon’s job in the guise of Chief Army Warrant Officer Roy Miller, who figures something is amiss when he leads his men on a third straight wild-goose chase. Ignoring orders to keep his mouth shut, Miller talks up the “bad intell” his special unit is getting at a closed-door meeting of big shots. Naturally, that draws many beady bureaucratic eyes his way, including two belonging to a CIA operative (the sturdy Brendan Gleeson), who not only believes Miller but agrees with his assertions.

Imagine that! A CIA boss as good guy, though character shades of gray in a Greengrass film always are more murky than clear black and white. Both sides offer mixed messages of patriotism and evil in the months just after the Iraq invasion in 2003, but a top administration official (Greg Kinnear) seems clearly motivated by something other than the angelic.

Even a Wall Street Journal reporter (Amy Ryan) is used in the latter’s political gamesmanship, if not a little something more, perhaps left on the cutting room floor from a movie that was completed in 2008. (Cynical types might suggest that positive publicity for “The Hurt Locker,” a far superior film, inspired this “Green” release.)

.Regardless — and believe it or not — the well-intentioned Miller remains left to roam freely in and out of Baghdad’s batty Green Zone. That is, until he sets his own sights on an Iraqi general who might really have some reliable info on the WMDs.

The whole shebang, with loud emphasis on the last syllable, is based loosely on the book, “Imperial Life in the Emerald City: Inside Iraq’s Green Zone,” which likely reads better than the film’s very basic screenplay from Brian Helgeland (“L.A. Confidential,” “Mystic River”)