In 1987, new-kid-on-the-block Fox attracted a teenage demographic by programming a gritty primetime show about baby-faced cops who go undercover at high schools. A quarter-century later, Columbia Pictures targets the over-17 set, reviving “21 Jump Street” as a raunchy R-rated laffer full of drug and dick jokes — an odd choice, since the radical genre switch seems best suited to those too young to have seen the original series. Still, by casting Jonah Hill and Channing Tatum as fish-out-of-water buffoons, the irreverent result feels fresher than most ’80s-show reboots, effectively flipping the address Johnny Depp made famous.

Hill, who pitched the pic’s producers on attempting “21 Jump Street” as an action-comedy, was 23 when he shot “Superbad,” and already he looked too old to pass as a high schooler. Now 28, the star has shed his baby fat and appears undeniably adult. Pair him with Tatum, 31, and there’s no way teens would mistake the duo as two of their own — a paradox that sets the tone for the film’s patently absurdist approach, which uses our willing acceptance of ridiculous genre conventions as a clothesline on which to hang its ruthlessly immature sense of humor.

High school was hell for Schmidt (Hill), a book-smart outcast with braces and a bad Eminem-style dye job. Jocks like Jenko (Tatum) had it relatively easy, though both were forced to sit out prom. That’s why their first big assignment after graduating from police academy — to infiltrate a high-school drug ring — feels less like punishment than a chance for a “do-over.” Older and wiser, the mismatched partners plan to apply the lessons learned the first time around to the case, only to discover that things have changed since they were in school.

Now, tolerance is cool, bullying is uncouth, and the popular kids (headed by Dave Franco) all look like well-coiffed extras from the Disney Channel. “I totally know the cause: ‘Glee,'” sneers Tatum, who hasn’t looked this comfortable onscreen since “Step Up,” embracing the awkwardness as he attempts to blend in with the science nerds, while Hill’s character fumbles his way through flirting with a student suspect (Brie Larson, putting the blah in blonde).

The operative idea here is that two guys who would have been rivals in high school have to buddy up to make it as cops. But instead of complementing one another, brainy Schmidt and brawny Jenko merely bring each other down, botching their first arrest attempt. After that debacle, the duo are reassigned to a canceled undercover project from the ’80s overseen by a surly captain (Ice Cube). “All they do now is recycle shit from the past and expect us not to notice,” quips their chief (Nick Offerman), in a line that hints at just how little respect the script, by “Project X” scribe Michael Bacall, shows its source. (Just wait’ll you see how it treats Depp’s cameo.)

Most of the humor concerns how inappropriate the language, behavior and attitudes are for the high-school setting, especially coming from grown men expected to act as role models: When it comes time to earn the drug dealers’ trust, they steal weed from the evidence lockup and throw the ultimate high-school party. These two may not look like teens, but they sure as heck don’t behave like cops.

Given the cartoonish way co-directors Phil Lord and Christopher Miller approach the premise, it should come as no surprise that the two got their start in animation. Together, they made the disaster-movie spoof “Cloudy With a Chance of Meatballs,” and they apply that same wink-wink sensibility to their live-action debut. Such a flip attitude serves the comedy well (the action feels more clunky), but belies just how insincerely everyone involved feels toward the story’s emotional core.

Maybe those raised on a diet of “Family Guy” don’t require the courtesy of a script that cares about its main characters, but why bother packaging the story as a male-bonding experience if the plan is merely to undermine it with vulgarities and homophobia? Where “Superbad” set the standard for mixing high-school sentimentality with gross-out humor, this lesser effort seems content redefining audiences’ idea of “dirty cops.”

Bringing composer Mark Mothersbaugh along for the high-energy assignment, the helmers make slick use of their new live-action collaborators. Considering that hardly anyone was asking for a “21 Jump Street” reboot, they’ve put their own playful stamp on it — which just goes to show what happens when a bunch of pot-positive cut-ups get their hands on a relic of Reagan-era anti-drug hysteria.

21 Jump Street

  • Production: A Sony Pictures Entertainment release of a Columbia Pictures, Metro-Goldwyn-Mayer Pictures presentation in association with Relativity Media of an Original Film/Cannell Studios production. Produced by Neal H. Moritz, Stephen J. Cannell. Executive producers, Jonah Hill, Channing Tatum, Ezra Swerdlow, Tania Landau. Directed by Phil Lord, Christopher Miller. Screenplay, Michael Bacall; story, Bacall, Jonah Hill, based on the television series created by Patrick Hasburgh, Stephen J. Cannell.
  • Crew: Camera (color, widescreen), Barry Peterson; editor, Joel Negron; music, Mark Mothersbaugh; music supervisor, Karen Glauber; production designer, Peter Wenham; art directors, Thomas Valentine, Scott Plauche; set decorator, Robert Kensinger; costume designer, Leah Katznelson; sound (Dolby Digital/SDDS/Datasat), Pud Cusack; supervising sound editors, Geoffrey G. Rubay, Jason George; re-recording mixers, Jeffrey J. Haboush, Chris Carpenter; special effects coordinator, Guy Clayton; visual effects supervisors, Richard Edlund, Helena Packer-Burnson; visual effects, duMonde Visual Effects, Colorworks, Pixel Magic; stunt coordinator, Jeffrey Gibson; assistant director, Jonathan Watson; casting, Jeanne McCarthy, Nicole Abellera. Reviewed at the Grove, Los Angeles, March 1, 2012. (In SXSW Film Festival -- Headliners.) MPAA Rating: R. Running time: 109 MIN.
  • With: Schmidt - Jonah Hill<br> Jenko - Channing Tatum<br> Molly Tracey - Brie Larson<br> Eric Molson - Dave Franco<br> Mr. Walters - Rob Riggle<br> Domingo - DeRay Davis<br> Capt. Dickson - Ice Cube<br> Zack - Dax Flame<br> Mr. Gordon - Chris Parnell<br> Ms. Griggs - Ellie Kemper<br> Principal Dadier - Jake Johnson<br> Deputy Chief Hardy - Nick Offerman With: Holly Robinson Peete, Johnny Pemberton, Stanley Wong, Justin Hires, Brett Lapeyrouse, Lindsey Broad, Caroline Aaron, Peter Epstein, Anthony Molinari, Luis Da Silva, Dominic Alexander, Mike Seal, Johnny Depp.