Jonah Hill, left, and Channing Tatum in “22 Jump Street.” (Glen Wilson/Columbia Pictures Industries)

When “21 Jump Street” gallivanted into theaters in 2012 with the impossible mission of reviving a dated and inherently implausible television franchise for the big screen, the key to its charm was its subversive take on high school.

Schmidt (Jonah Hill), a former nerd and social outcast, finds that his affinity for theater and his ability to talk to girls make him popular when he goes undercover at a moment where a social conscience and good grades are the keys to cool — and discovers that he is capable of being as cruel as his former tormentors. His partner and high school bully Jenko (Channing Tatum) is initially disconcerted when he is tracked into honors classes, but for the first time in his life he learns what a pleasure education can be. “21 Jump Street” was charming because it subverted audiences’ expectations for the high school experience while tweaking the characters’ expectations for themselves.

The sequel, “22 Jump Street,” which arrived in theaters this weekend with a cheerful, lewd and very profitable bang, is not quite as successful. In between riffing on the conventions of Hollywood sequels and the homoeroticism of hypermasculine friendships, the movie’s vision of college never quite jells. That is too bad: Our debates about campus attitudes toward free speech and the sexual culture of college could have used a vigorous and funny intervention.

One of the funniest moments in the film comes in the opening scene, when we meet back up with Schmidt and Jenko, who have been assigned to do surveillance on the “University of Internet,” a clear rip on primarily-online programs like the University of Phoenix. A professor in the school turns out to be passing messages about drug deals during his broadcast lectures.

Rather than taking aim at the proliferation of such programs and the quality of the education they provide, “22 Jump Street” moves on to a long and silly car chase. That choice sets the tone for much of the movie.

The brick-and-mortar institution Schmidt and Jenko eventually attend seems to be part of a fictionalized University of California System, where the football team hovers somewhere below Division I, but there is a vigorous arts program. And once there, “22 Jump Street” tends to hit the expected beats on cue, rather than diving through them head-first and making joyful, clangorous noise, as was the previous film’s wont.

Jenko goes out for the football team and rushes the fraternity headed by his quarterback Zook (Wyatt Russell), where the ability to open beer bottles with one’s eyeballs remains a valuable social asset. “22 Jump Street” has some fun with the implication that Zook might be gay and in love with Jenko, but it spends far too much time on the idea that sex between the two men would be inherently hilarious (and it makes one very nasty joke about transgender people) to be in any way challenging.

It would have been far funnier for “22 Jump Street” to follow Jenko to his human sexuality class and to explore his revelations there, or even to embed him with college gay rights activists.  “Did you know I used gay slurs in high school?” Jenko asks Schmidt excitedly in their early days of class. “Yes, directed at me,” Schmidt tells him, wearily. Later, Jenko blows his cover to lecture a group of drug dealers on their use of homophobic slurs.

“21 Jump Street” was genuinely joyous when Jenko embraced science; “22 Jump Street” could have done the same thing for his newfound activism. Sometimes, the impulse to basic decency, expressed in humane and reasonable terms, is a genuinely challenging idea. 

It falls to Schmidt to explore the changing sexual mores of campus after he starts hooking up with Maya (Amber Stevens), who appears to have read “The End of Men.” She tells Schmidt that she is mainly interested in sex, rather than in spending the time developing a relationship, because she would rather focus on her schoolwork and activities.

If “22 Jump Street” had the heart to explore a full-on change in mores, it might have shown other guys walking back to their own dorm rooms after spending the night somewhere else. Instead, the joke is that Schmidt is acting like the other girls who make that regular trip home, carrying their shoes with them.

After the full-on rewrite of high school cliques that made “21 Jump Street” so fresh, turning Jenko and Schmidt back into the same, stereotyped figures they were in high school feels more than a little stale.

The best character in the movie is Mercedes (Jillian Bell), Maya’s acerbic roommate. Suspecting that Schmidt is too old to be in college, she lays burn after burn on him, demanding that he “tell us about the war. Any one of them.” Mercedes turns out to be the big drug dealer on campus, her prim outfits covering up for a serious knowledge of designer drugs and a nastily aggressive streak.

Mercedes is also the film’s purest expression of timely stereotypes of college students now. Her raging entitlement about grades makes her a ruthless criminal: “I framed my psych professor for giving me a B-. She’s in jail now,” Mercedes tells a group of low-level distributors.

Her notion of gender equality is hilariously skewed. When Schmidt confronts her and tries to arrest her, he is reluctant to use force. “If you thought of me as a person instead of a woman, you’d hit me and not feel bad about it,” Mercedes snarls.

And she has a particularly confused sense of sexual culture. When they start fighting, Mercedes assumes Schmidt’s attempts to subdue her are a come-on. “You’re Mr. and Mrs. Smithing me!” she declares when Schmidt insists that he is doing nothing of the kind. It is hard to think of a purer statement of screwed-up sexual expectations than the idea that violence is a come-on, but “22 Jump Street” has helicopters to explode in lieu of digging deeper into this idea.

“22 Jump Street” might have been a brilliant, even necessary movie about the state of college. Instead, it tastes more like a warmed-over Pabst Blue Ribbon: fine, unless you know there is better out there.

Alyssa Rosenberg blogs about pop culture for The Washington Post's Opinions section.