The best war movies don't preach against war: They remind us of the costs for soldiers and families and ask us to consider whether those costs are worth paying.

“The Messenger” does that without firing a bullet or putting us on a battlefield. It joins the front rank by making us wonder what America should do about Iraq and all future Iraqs on our strife-torn Earth.

The best war movies also depict soldiers neither as heroes nor demons nor madmen, but as people who have all those qualities in some measure. Will Montgomery (Ben Foster) is a hero for his willingness to put his safety behind that of the men in his platoon and a demon in his tendency to devalue life after a debilitating accident. He worries he may turn into a madman, but he's saved from that fate when he's assigned to a U.S. Army casualty notification team. While bringing tragic news to other people, he humanizes himself.

Sgt. Montgomery, an Iraq war vet, becomes the sidekick to Capt. Tony Stone (Woody Harrelson), who has codified the grief-delivery process: no personal introductions, no touching next of kin in consolation, use of a minimum of words. Stone's a career officer, and he has rules for every situation, from his tenuous sobriety to his cavalier attitude toward women.

Montgomery tries to follow some of those rules. But his unconventional attitude, which has already cost him a longtime girlfriend (Jena Malone), leads him into a relationship with a new war widow (Samantha Morton) who has a young son.

Writers Alessandro Camon and Oren Moverman don't suggest the Army has to be a dysfunctional family: It suits Stone, who can't imagine functioning as a civilian. Just as the film doesn't insist we should leave Iraq, it doesn't insist Montgomery should leave the service.

In fact, Moverman's directing debut stubbornly resists all kinds of clichés. The vet and the war widow have no romantic epiphany. When Stone and Montgomery crash a party of rich people, they don't speak the kind of blunt truth Hollywood likes to put into such characters' mouths; they humiliate themselves and stagger drunkenly across the parking lot, playing war games like children.

Harrelson does a satisfying, tight-lipped job as Stone. But this is Montgomery's story – the film's title is singular, not plural – and he evolves from a potentially suicidal wreck to a more fully alive person.

Foster has played powder kegs and psychos in “Alpha Dog,” “3:10 to Yuma,” “X-Men: The Last Stand” and other films. He brings similar intensity to Montgomery, but he softens slowly: Under the closed-off soldier waits the man capable of sustaining a loving relationship.

The most powerful sequences come when the men deliver their news. One of the bereaved (Steve Buscemi) flies into a rage, asking Stone and Montgomery why his son had to die in Iraq. They don't answer him, because there's nothing useful they can say. They just leave him – and us – wondering if that particular fight has been worth its price.