The big achievement of “Whiskey Tango Foxtrot” is that it does two things simultaneously that would seem to be in contradiction. It presents life as a Western journalist in Afghanistan as horrible in every way — dangerous, ugly and miserable. And it also shows how that life could be attractive, even addictive. Moreover, it doesn’t just tell you this, but makes you feel it, so that you end up envying people in one of the worst places on Earth.

Based on “The Taliban Shuffle,” a memoir by Kim Barker, “Whiskey Tango Foxtrot” stars Tina Fey as Barker, the Chicago Tribune’s South Asia bureau chief from 2004 to 2009. The movie changes things a bit. Here Barker is a copy writer for a TV network when she impulsively volunteers for the Afghanistan assignment. This little alteration makes the character more of an innocent abroad, while conveniently making her business less cerebral and more visual.

She has a baptism by fire in an early scene. Working as an “embed” with the Marines, she’s part of a convoy that’s attacked by insurgents. With machine gun bullets bouncing off the vehicle, she nervously unbuckles her seat belt, and the first thing we think is that she is about to panic. Instead, she picks up a video camera, jumps out of the truck and starts shooting the battle from inside the thick of it.

This is an important moment in several ways. First, Fey persuades us to believe this woman would actually do that. Second, it’s the moment when we realize that this is the story of an extraordinary person, someone who might seem ordinary in most ways, but has drives and impulses that can only be answered by this kind of mad environment. Third, it signals that “Whiskey Tango Foxtrot” is not a comedy as we usually understand it. It’s more like an unblinking presentation of absurdity on a mass scale.

Robert Carlock’s screenplay is impressive in what it doesn’t say. No one ever mentions that the appeal of this life is intimately entwined with the possibility of being dead the next minute. It’s just understood. Suddenly this woman is riding helicopters into war zones, and we get it. This is not life as we usually know it, with thoughts stuck in the past and anxieties about the future. This is nothing but now, which makes life inside that rickety hotel, where Barker lives with other journalists, a kind of middle-aged, booze-soaked version of the last days of Pompeii. Like spring break with wrinkles.

The story is a journey for Barker, but it’s one the audience has the experience of sharing. So we start, as she does, huddled in the hotel and hearing the sound of distant gunfire, convinced this is a hellhole and wanting to escape. And we end up, very soon, feeling the addict’s dilemma, wondering if today is the day to stop, or if one more high is worth the risk.

Margot Robbie plays Tanya, Barker’s best friend and professional rival, and it’s a real asset to have someone with that kind of star wattage in a supporting role. She’s utterly believable as a TV star, but she fills in the character’s undercurrents as well, suggesting there is something slightly wrong with her, as though she’s found a semi-healthy channel for self-destructive impulse. Martin Freeman plays a roguish Scottish photographer, and at first the role seems odd casting for an actor of Freeman’s sensitivity. Then it doesn’t.

“Whiskey Tango Foxtrot” is by far Fey’s best movie. It makes use of her comic sense, but also of her watchful wariness and underlying wistfulness. Directors Glenn Ficarra and John Requa have complete command of the movie’s tone, and the screenplay never forces Fey into doing anything fake. There are none of the false conflicts and crises that you get in the last third of most comedies. In fact, one of the best things about “Whiskey Tango Foxtrot” is that it has no particular climax at all.

In place of a story with a classic structure, we get an emotionally honest rendering of an episode, like something really interesting that happened in somebody’s life. And so, it feels real.