Channing Tatum Is Funny. Really. 21 Jump Street, Reviewed.S

1. It's surprising that it took this long for someone to mix the peanut butter of Apatowian bromance comedies with the chocolate of the buddy cop film. They're natural allies, with their undercurrents of false machismo, crippling fear of women and unmistakable male panic. It's tough not to lament the buddy cop formula, really; it had a built-in structure the same as a musical or a horror film, and the pleasure was in the variations on the cliche rather than its repetitions. (Done right: Lethal Weapon. Done wrong: Collision Course.) But the buddy cop genre had turned so hoary that you couldn't even do one anymore without parodying the whole idea, done well in The Other Guys and done even better, alas, in 21 Jump Street, a brand-name retread that, as it turns out, is far, far more fun than it has any right to be. It falls apart over the last half hour, but for the first hour, this is a frenetic, legitimately inspired comedy. Really.

2. The premise of 21 Jump Street is familiar, I suspect, to far fewer people than this film's creators would like to think. (I always just knew it as the teeny-bop show Johnny Depp was embarrassed by.) Two young-looking cops are assigned to a local high school to ferret out a drug ring and end up embroiled in the day-to-day social nightmare that is secondary education. Here, Schmidt (Jonah Hill) is the nerd who was bullied by Jenko (Channing Tatum) when they were in high school, before becoming pals as adults. (Sorry, "adults.") They return to school—bossed around by an amusing-for-the-first-time-in-decades Ice Cube—and discover it dramatically different than they remembered. It's a basic buddy-cop, fish-out-of-water comedy that, when attached to the TV franchise's name, must have been a staggeringly easy studio pitch. But all that matters is the execution.

3. The movie has two great jokes which it milks constantly. The first is the obvious one, that these are terrible cops, not too far removed from Seth Rogen's and Bill Hader's characters in Superbad, who don't know how to use their guns, constantly blow their cover and have a level of emotional development far below the students whose world they're supposed to be infiltrating. The second idea is the most inspired one. Tatum swaggers into the school thinking that the trick to being popular is being a rebel, randomly getting in fights and not caring about anything, but it doesn't work like that anymore. These days, in the movie's universe, the cool kids are environmentally conscious, tolerant of those different than them and compulsive overachievers and resume-builders. In this school, the bully jock character sings folk songs about trees, disdains organized athletics and has already been accepted to Berkeley. Schmidt, gawky and awkward but intelligent, ends up the popular one while Tatum, the traditional dumb hunk, is shunned and mocked. It's an extremely funny idea—the notion that conservationism and tolerance have evolved so much in just the last five years that the gays and poets have triumphed over the athletes in the high school hierarchy—and it's one the movie doesn't stop mining.

4. Any buddy-cop bromance lies on the shoulders of its stars, and I'm a bit surprised to report that Hill and Tatum are a legitimately charismatic team. Hill's obvious self-regard as a performer works for him here as a smart nerd who isn't so smart and isn't so nerdy, but the real find is Tatum who, it turns out, has a funny bone after all. He has the lunkheaded, game-for-whatever charm of Election-era Chris Klein and is better at honing in on what's funny about a particular line than, say, Mark Wahlberg. Channing Tatum has been forced down our throats for several years now—he's sort of a younger Sam Worthington in that way—and this is the first time I've understood why. Maybe Steven Soderbergh knows something after all. The film is also populated with terrific comedic actors in smaller parts, from Chris Parnell to Ellie Kemper to Nick Offerman to Rob Riggle, and even gets the high school roles right, with James Franco's little brother Dave, YouTube star Dax Flame (who's not bad, all told) and, most effectively, Brie Larson in the thankless role of Person Who Has To Convincingly Kiss Jonah Hill. It all leads up to a final act dual cameo that, even if you know it's coming, will still have you roaring.

5. The movie's tastes still run a bit further toward the scatological than might be entirely necessary—I audibly groaned when we got yet another penis closeup. This is becoming this decade's "shocking" equivalent of when '80s films started showing pubic hair—and every 25 minutes or so, it starts thinking it's an action film when it absolutely is not. (There's a 10-minute car chase that feels endless and would be a good time for a nap.) But this movie is a lot smarter and a lot funnier than it has any real right to be. I'm not sticking around for the inevitable sequel set in college, and you probably shouldn't count on Hill & Tatum to be the next Hope & Crosby or anything, but I can definitely say this is the best movie based on 21 Jump Street humanly possible.

Grade: B.

Grierson & Leitch is a regular column about the movies. Follow us on Twitter, @griersonleitch.