A little bit of Tracy Morgan goes a very long way, and there’s an awful lot of him in “Cop Out.” But even that isn’t the major drawback to Kevin Smith’s buddy-cop comedy. The real problem is that it wants simultaneously to be a send-up of the genre and to generate the excitement a serious example of it would. It fails on both counts.

You can think of Jimmy (Bruce Willis) and Paul (Morgan) as Smith’s (or more properly writers Robb and Mark Cullen’s) version of the Mel Gibson-Danny Glover “Lethal Weapon” duo, except that this time the black guy’s the goofy partner and the white fellow the serious one. Of course they have a sweaty captain (Sean Cullen, presumably a relative of the scripters) who’s irate about their reckless screwups. After one such incident involving a murderous drug pusher they’re put on suspension—just when Jimmy needs big bucks to pay for his daughter’s enormous wedding. And the fact that his ex-wife’s rich hubby (Smith favorite Jason Lee) offers to pick up the tab makes him all the more determined to do so himself.

So he decides to sell his one treasure—a valuable mint baseball card. Unfortunately, it’s stolen from him by a goofball thief (Seann William Scott), and the attempt to retrieve it will bring him and Paul up against a Mexican drug kingpin named Poh Boy (Guillermo Diaz), who will return it only if they track down a car that’s been stolen from him. It turns out to contain, in the trunk, a hostage (Ana de la Reguera)—who then becomes the plot’s McGuffin. Car chases, shootouts and other instances of mayhem ensue, punctuated by riffs from Morgan—the first at the very start, when Paul interrogates a suspect by repeating lines from movies he’s seen (a gag made even worse when Jimmy, watching from behind the glass, tells us each title as the allusion passes—a sure sign the makers think we’re idiots)—whose character, in one of the least inspired of the story threads, suspects that his wife is cheating on him. There’s also another pair of detectives on hand, played by Kevin Pollack and Adam Brody, who are rivals to our heroes but ultimately good guys too.

The workings of the drug plot are at once convoluted and simple-minded, and having Poh Boy make his initial entrance in a Catholic church (and even killing somebody there) is especially distasteful. But complaining about a lack of taste in a Kevin Smith movie is rather like ordering the sun not to rise. The humor is of the crude slacker variety—the sort of stuff a pimply adolescent might think hilarious but anybody with an IQ in double digits will find puerile. (Much of Scott’s turn consists of repeating everything other people say to annoy them—a gag that certainly went out in sixth grade.) Then there’s the gratuitous sexual and scatological stuff, which points to a total poverty of invention.

But even if the script—the first directed by Smith that he hasn’t written himself—is several steps below mediocre, it needn’t have been so sloppily done. Smith’s been making movies for fifteen years now, but he seems to have learned little beyond the rudiments. The compositions are still flat, the transitions clumsy, the pacing meandering. And he fails to elicit anything interesting from his actors, letting them either coast (like Willis, who could have phoned his performance in) or go completely bonkers (like Morgan, who’s typically unrestrained, or Diaz, who’s even worse—if you remember Jay Robinson in “The Robe,” you’ll have some idea of just how far he goes). Then there’s Scott, who seem to be having a lot more fun playing a zonked-out frat boy type than we do watching him.

Technically “Cop Out” is as indifferent as it is in other respects. Michael Shaw’s production design, Jordan Jacobs and Jonathan Arkin’s art direction, Chryss Hionis’ set decoration and Juliet Polcsa’s costumes are mediocre across the board, and David Klein’s cinematography goes from glaring to murky. Presumably Harold Faltermeyer’s chintzy synthesizer score—accompanied by a few old tunes—is intended to imitate those heard in old buddy-cop movies, but it’s still pretty bad, even if that’s intentional.

Maybe this should have been called “Opt Out.”