The man fires a rifle for many years, and he goes to war. Afterward, he turns his rif le in at the armoury, and believes he's finished with the rif le. But no matter what else he might do with his hands - love a woman, build a house, change his son's diaper - his hands only remember the rifle." This clunky little nugget of prose is drawn from Anthony Swofford's 2003 memoir Jarhead, about his time serving in the first Gulf War. It begins and ends Sam Mendes's new film version of Swofford's book, intoned in suitably portentous voiceover by star Jake Gyllenhaal.

Gyllenhaal plays Swofford, who was 20 when he was posted with the Marines to Saudi Arabia - there to fanny around a lot with his new buddies, get sweaty in the desert heat, freak out about the questionable fidelity of his girlfriend at home and experience very little combat. Indeed, that rifle quote is a peculiar choice to bookend the film, since Swofford's book and William Broyles Jr's screenplay both make a particular point about just how little shooting the lad actually got to do. The weighty language is typical, however, of a film that's more interested in the construction of solemnly resonant War Movie Moments than in saying anything precise or meaningful about the conflict it depicts. Jarhead has been described as controversial, presumably due to the fact that it shares its geographical setting with a certain ongoing spot of military bother. What's truly shocking about Mendes's film,

however, is how equivocal it manages to be. As a director, Mendes makes a great spin doctor. Every issue is glossed to appeal to both sides of the argument; every controversial moment feels as if it's been approved by a succession of focus groups. Not quite cynical, not quite gung-ho, fastidiously removed from any risky real-world politics, Jarhead is a very modern war film: one that presents war not as noble duty, cruel ordeal, or necessary collective endeavour, but as a sort of post-modern nervous breakdown.

A jarhead is slang for a Marine and refers to the flat-top haircut that helps reduce them all to one amorphous mass of obedient, malleable macho muscle. Swofford, however, has a bit more in his jar than most: he is an intellectual, or so we are invited to believe, who keeps a Camus paperback amid his effects and who explains to a drill instructor that, "I got lost on my way to college, sir!" Publicity for the film - not to mention the casting of Gyllenhaal - plays up Swofford's smarts. The press notes invoke J D Salinger with gay abandon: "As if J D Salinger's Holden Caulfield had been deployed to the Gulf"; "As if Salinger were dealing with the Gulf War." If I were Salinger, I'd pole-vault out of my seclusion and tell them to stop using my name in vain. Swofford might share Caulfield's self-involvement, but Salinger's tenderness and irony is nowhere to be found in Jarhead. Swofford in the

Gulf reads more like a foul-mouthed, less funny cross between Adrian Mole and Ferris Bueller: feckless, thrillseeking, showily bitter in that adolescent way. His sarcastic style conveniently absolves Mendes from infusing his film with anything so dangerous as earnestness or opinion. When a more pensive grunt queries the US agenda in the Gulf ("Who do you think gave Saddam all his weapons?"), Swofford is dismissive: "F*** politics. We're here. All the rest is bullshit."

By romanticising the jaded selfregard of the post-Vietnam soldier, Jarhead divorces American warfare from its economic and imperialist functions, and portrays it as a mere job of work - an outlet for young men's existential frustrations and a noble profession for stand-up blue-collar guys such as Jamie Foxx's platoon leader. The film's frequent references to other war movies add to the sense that the Iraq situation of the past 15 years strikes Mendes merely as an intriguing cultural construct - stitched together from bits of Catch-22, Apocalypse Now, Platoon and Full Metal Jacket - rather than an ongoing real-life bloodbath. Everyone's part of some crazy kaleidoscope; no-one's responsible and nothing's quite real. Mendes prefers the dumb, pretentious faux-savagery of Swofford's MTV-kid prose ("As a young man raised on the films of the Vietnam war, I want ammunition and alcohol and dope, and

I want to screw some whores and kill some Iraqi motherf***ers") to the genuine savagery of what's really happening out there.

Savagery is also kept at a distance in Christian Carion's Merry Christmas, a European co-production based on the tales of impromptu fraternisation on the Flanders front at Christmas 1914. If Jarhead conceals the enemy almost entirely, Merry Christmas makes goodie and baddie indistinguishable: it's a piece of moist-eyed wishful thinking that fantasises a brotherhood of softhearted chaps who'd far rather be exchanging hugs and family photos than bullets. Carion's film may be less cynical than Jarhead - it at least has an agenda, albeit a cloying and pointlessly idealistic one - but it offers no more persuasive evidence that the contemporary war movie knows what it's doing. With political correctness having ruled out the sort of propaganda f lick that pits a shifty-eyed enemy against a heroic home side, and mainstream filmmakers seemingly lacking the sort of boldness or imagination that would

produce truly illuminating, mature commentary, we're left stranded between lily-livered pacifist fantasies and heartless, masturbatory macho war games. Ironically, it's vintage re-releases - recently, Stanley Kubrick's Paths of Glory; next year, Jean Renoir's La Grande Illusion - that currently provide the most pointed commentary on the cruelties and complexities of war.

Merry Christmas (Joyeux Noel) is out now. Jarhead comes out on January 13. La Grande Illusion is re-released in 2006.