Former Saturday Night Live player Tracy Morgan has by now trademarked the dizzy persona that has served him well on the NBC ensemble comedy 30 Rock and here, in Kevin Smith’s weightless new farce, as a New York cop hunting a vicious gang leader and a stolen baseball card. He is self-absorbed, endearingly eccentric and rarely at a loss for words, especially when logic escapes him. He’s never all there.

The character is a more or less sanitized approximation of the brazen goofball Morgan plays in his stand-up act, and as one half of the buddy duo in Cop Out – Bruce Willis plays his straight-man partner with a knowing wink – he proves his charisma is no fluke. Absent 30 Rock creator Tina Fey, his star still shines.

In other words, Morgan has the talent to transcend his TV roots, but he’s going to need a sturdier vehicle than Cop Out to do it. Smith, who rarely directs scripts he doesn’t write himself, makes an exception here, and the results are depressingly meager. Seventeen years after Clerks made unexpected splashes at the Cannes and Sundance festivals, Smith’s greatest strength remains his gift for playfully profane wordplay. His productions are rarely elegant, but usually effective.

Cop Out is neither. In hiring “Axel F” composer Harold Faltermeyer to provide the movie’s original score, Smith was clearly trying to evoke memories of Beverly Hills Cop (1984), a superior action comedy that accelerated the rise of another SNL vet, Eddie Murphy. If anything, Smith’s contribution to the genre, with its clumsily shot action sequences and plodding pace, suffers the comparison poorly.

The actors seem to be having fun, at least. Willis has played this kind of character before, most famously in the Die Hard movies. The biggest difference between John McClane and Jimmy Monroe, the world-weary cop he plays here, is the urgency their missions demand. McClane is America’s last line of defense against terrorism. Monroe is tracking down a baseball card valuable enough to finance his daughter’s wedding.

If that sounds like a dubious premise, it is, but Cop Out never treats Mark and Robb Cullen’s story as anything more than an excuse for Willis, Morgan and sometime sidekick Seann William Scott, on hand as a smarmy thief, to trade barbs that too often fall flat. Only Morgan reaches the heights of inspired silliness to which the movie aspires, though not nearly enough to redeem Smith’s shoddiest outing to date.

Note: Smith recently appeared on a satellite radio show, complaining that critics “didn’t get” the movie. In the interest of full disclosure, I should admit that I’m a Smith fan, willing to defend even minor offerings like Jay and Silent Bob Strike Back. I don’t mind his assertion that critics are “playing an old game in a new world” – if you’re willing to dish it out, you have to be willing to take a few lumps yourself. But his claim that Cop Out’s detractors failed to understand its central conceit is a crock. This is not a sophisticated comedy. Everyone gets the jokes – they just weren’t very funny.