One has to give Glenn Ficarra and John Requa credit for trying to do for the war in Afghanistan something akin to what Robert Altman managed for the Korean conflict in “M*A*S*H.” Unfortunately, Robert Carlock’s script for “Whiskey Tango Foxtrot”—adapted very loosely from Kim Barker’s memoir “The Taliban Shuffle: Strange Days in Afghanistan and Pakistan”—doesn’t maintain the air of brittle absurdity that might have turned the film into a worthy companion to Altman’s classic or even “Dr. Strangelove.” Instead the picture is content with mild, obvious plot points, and in the end even descends into clichéd action-movie mode and uplifting emotional catharsis.

Perhaps that’s because the movie was fashioned as a vehicle for Tina Fey, who tries to invest her flustered comic persona with a more serious vibe, but without much success. The result is less edgy than feeble, much like Sandra Bullock’s misfire “Our Brand Is Crisis” was.

Fey plays a version of Barker, none too imaginatively rechristened Kim Baker, who’s not the newspaper journalist of the book (and real life) but a news producer for a 24-hour cable channel. In 2004, tired of preparing copy behind the scenes to be read on camera by others, she agrees to be tapped for a stint as a network field correspondent in Afghanistan. Her boyfriend Chris (Josh Charles) isn’t terribly happy that theirs will turn into a long-distance relationship, but agrees to the one-year gig.

After a white-knuckle landing at Kabul Airport—which her cynical seatmate, Scottish free-lance photographer Iain MacKelpie (Martin Freeman), refers to as KIA or “Killed in Action”—Baker finds herself thrust into a wild, woolly journalistic world. In addition to Iain, who comes on to her immediately (and, of course, drinks heavily), she becomes a colleague of blonde bombshell reporter Tanya Vanderpoel (Margot Robbie), who shows her the ropes. She also links up with her gentle but firm Afghan aide Fahim Ahmadzai (Christopher Abbott), her gawky photographer Tall Brian (Nicholas Braun) and her security man, handsome New Zealander Nic (Stephen Peacocke), who become her travelling companions, as well as local Marine Corps General Hollanek (Billy Bob Thornton, strutting implacably), who with some misgivings allows her to embed with his men when they go on patrol but not to bed with them otherwise.

The thrust of the picture is Kim’s gradual acclimation to the culture and to the realities of the conflict, which has become America’s forgotten war by comparison to the invasion and occupation of Iraq. She finds it increasingly difficult to get the producers back home to air her reports, even as she tries to remain faithful to Chris—until an unfortunate, all too predictable Skype chat intervenes. Her commitment to him has already been challenged by the come-ons of Ali Massoud Sadiq (Alfred Molina), a government official who’s soon appointed Attorney General and offers her contacts among the warlords in return for a bit of intimacy. Now it’s entirely replaced by a romance with Iain, which has a professional collaborative element that has potentially devastating implications when he goes off alone on a long-planned investigation after she abruptly returns to New York to consult with her boss—a trip that shows there are betrayals at home as well as back at the front. The upshot is the enlistment of Hollanek in a mission that could have important consequences for everyone concerned.

There are a few sharp elements here. Some of the performances are excellent: Thornton delivers an appropriate degree of brusque efficiency; Freeman—after a long period of playing recessive, quiet characters—gets to cut loose and even be the leading man; Peacocke makes a likable lug and Braun a goofily engaging colleague; Abbott fashions an affecting portrait of a good man struggling to maintain his integrity interacting with foreigners in a war zone; and Molina is hilarious as a slimy official with some distinctly inappropriate ideas on his mind. But Robbie fails to convince as a hard-bitten striver, and though Fey makes a game effort, she never escapes the feeling of performing in an extended SNL sketch.

It’s not the actress, however, as much as the script that hobbles the picture. Carlock simply never finds the proper balance between the serious and the jokey, and never manages to bring the background—the war itself—into focus, instead simply concentrating on the education of Kim that leads to her growth as an independent woman. The screenplay goes seriously awry toward the close, with the introduction of a rescue mission that’s all to easily arranged and executed, and a coda involving a serviceman (Evan Jonigkeit) whom Kim had earlier interviewed that’s intended to be cathartic but comes across as an awkward attempt to end things on a soothing note.

On the other hand, though they might not always use Fey to best advantage, Ficarra and Requa do get some cheeky work from the supporting players, and working with cinematographer Xavier Grobet they employ the New Mexico locations effectively as a stand-in for Afghanistan. The rest of the production team—editor Jan Kovac, production designer Beth Mickle, art directors Elisa Viola and Derek Jensen, set decorator Lisa Sessions Morgan and costume designer Lisa Lovaas—do serviceable work, but Nick Urata’s score is forgettable.

“Whiskey Tango Foxtrot” doesn’t deserve the exclamation the first letters of its title invites, but in the end it’s not challenging, incisive or funny enough to merit much more than a shrug.