Woody Harrelson, right, and Ben Foster star in “The Messenger.”

In a sense, the soldiers at the center of “The Messenger” are engaged in house-to-house combat. Capt. Tony Stone (Woody Harrelson) and Sgt. Will Montgomery (Ben Foster) are unwelcome visitors, wary of what might detonate behind the next door.

They’re no longer fighting in Iraq, however. They’re Army Casualty Notification officers, delivering tragic news to everyday New Jersey families within 24 hours of the soldier’s death.

They have protocols to follow — stick to the assigned script, don’t try to console, leave the area promptly — but there’s no manual for dealing with explosive emotions. There are several notification scenes in the course of the film, filmed in long takes of excruciating tension and immediacy. One woman slaps them. A man curses and spits. Others faint, collapse in tears or vomit from shock.

This is a poignant war movie, but it’s also a buddy movie with a difference, one that’s both funny and bleak. Will and Tony are an ungainly two-man unit. Will, recuperating from a combat wound to his eye, might as well be stenciled “Contents Under Pressure.” He wants to wait out the final three months of his tour in peace. He has no desire to ambush unprepared civilians with the news that they’ve lost a brother or a sister or a husband.

Tony, an Army lifer, is foul-mouthed, cynical but decent, a square-jawed Sgt. Rock type. He has been making house calls long enough to know the grim tricks of the trade: Park somewhere inconspicuous, avoid physical contact, never use euphemisms that could mean “not dead.”

“The Messenger” has a sharp eye for social and economic class realities, and a sensitive ear for authentic American speech. Remarkable, considering the script was written by an Italian (Alessandro Camon) and an Israeli (Oren Moverman, who also capably directed).

The story’s simmering power comes from the erosion of those regulated responses in the face of battering emotion. Will feels himself emotionally drawn to a war widow, observing her at a distance as if she were a surveillance target. Tony, feeling a kinship with his new partner, reaches out to him, simultaneously bluff and awkward. After a day of grim duty that has him all wound up, he asks Will, “Do you instant-message?” They are protected by military life yet stifled in ways they can’t express.

The film is apolitical, insofar as a story about families scarred by war can be. There’s a sense of balance and intelligence in every scene, and the characters grow in ways that surprise us while remaining consistent with their natures.

My only misgivings are quibbles. I wished Will didn’t steadily put drops in his wounded eye, which can’t form tears — symbolism overload. Most of the people the messengers call on are played expertly by unknown actors. Two have semi-famous faces, and while they are also excellent, they broadcast on a different wavelength.

“The Messenger” is a rare breed of Iraq war movie, one that’s not merely well-intentioned but supremely well made.