At the beginning of "21 Jump Street," Ice Cube, in his supporting role as chief of a police task force that goes undercover into high schools and colleges, orders the protagonists to embrace their stereotypes. The stereotypes in question are geek and jock, and the embracing of them in this oddly charming comedy becomes a kind of pop art. Its source material, a late-'80s television show that gave Johnny Depp a leg up into stardom, is stripped down to hardly more than spoof, but it pulls off a decent show of ironic self-mockery and vandalized stereotypes to be a revitalizing entry in a tired genre.
The lead actors themselves, who might make a more pretentious critic groan, successfully embody their respective cliches. When we first meet Morton Schmidt (Jonah Hill) in 2005, his senior year of high school, he is a chunky, self-styled Slim Shady who is at the less-prestigious end of the jock-geek continuum. His locker-pounding nemesis is Greg Jenko (Channing Tatum), who laughs when Schmidt's attempts to ask a girl to prom are batted down before he can even bring up the question. Seven years later they're both recent graduates of police academy, and have overcome their adolescent differences in order to unite as a bromantic pair of incompetent cops. Their mishaps earn the ire of the commander, so they're sent to a special undercover police unit headed by Ice Cube, who humorously embraces his own angry black guy stereotype. Right away they are assigned to infiltrate their old high school to determine the source of a home-cooked psychedelic drug that students have been enjoying, sometimes with fatal consequences.
They land in the usual Hollywood high school utopia, a bizarre conception of what it might be like to return to that pimply era as a fully self-actualized adult: Everyone's actually college-aged or older, way too good-looking, concerned only with prom and popularity, and the parents are always leaving for the weekend. All the students are sorted into a very self-evident jock-geek continuum that Schmidt and Jenko, aliased as brothers, happily recognize from their own high school days. Schmidt has high hopes that he will be able to do it better the second time around, but before even making it to class they mismatch their identities, and he gets sent to drama class rather than AP chemistry, where the neanderthalic Jenko ends up instead.
This confusion, however, allows Schmidt to enter a clique of cool kids whose diversity, eco-friendliness and collegiate expectations make them an affront to the comforting stereotypes. Among them is Eric (Dave Franco), who it turns out is dealing the drug in question. Schmidt, though, is looking for the supplier; he penetrates their inner circle with such zest that he loses sight of the mission in favor of Molly (Brie Larson), his new crush, as well as flattery from Eric and the others. In the meantime Jenko does his darndest to protect his duty as a policeman, and in doing so falls in with the bespectacled science dorks that were once his foils, thus deepening the role reversal.
On paper it may be hard to believe, but "21 Jump Street" is way better than it sounds. Given its genre and lead actors, it's not asking for high standards, so its success as a cliche-buster is pretty precise. There's nothing outright offensive about it, despite the fact that Hill and Tatum's rapport frequently relies on "no homo" gags, some rather grotesque physical humor and occasional swerves into political incorrectness. It stays true to the essential comedic angle — the genre itself — which, with the combined pools of high school and incompetent cop movies, overflows with material to plumb. It's sufficiently meta concerning the reappropriation of stereotypes, especially at the start, allowing the story to eventually get away with the unbelievable and the obvious (a limo chase scene, a nicely-delivered Johnny Depp cameo).
If you just aren't into spoofs, it won't bring upon a sea change. But in a Hollywood clogged with pastiches and easy recyclables, it's a goofball comedy that doesn't necessarily have to be a guilty pleasure.