Debilitatingly witless, “Identity Thief” strands Melissa McCarthy and Jason Bateman on the shoulder of its own road-trip premise.

The screenwriter of “Identity Thief,” Craig Mazin, gave us “The Hangover Part II.” All these pictures belong to the same realm of exhausted, mean-spirited comedy, pushing casually sadistic mayhem in the guise of slapstick, destined to make millions on the backs of its actors. You can’t really talk about any of these pictures in terms of their comic machinery because, at heart, they’re barely comedies. They’re situations in search of comedy.

All McCarthy has to do is show up, and the audience likes her, even when the audience is supposed to hate her, or when “Identity Thief” treats her character — a brazen Florida con woman living large on the Visas of others — like a feral, subhuman pathos dispenser.

When Denver accounts representative Sandy Patterson, played by Bateman, discovers his identity has been purloined and his credit cards are maxed out, his employer (John Cho) declares him a bad risk for their startup company. Sandy is given one week to retrieve the con woman; bring her to Denver, all the while being tailed by drug dealers and a murderous bounty hunter; and turn her over to the police, thereby clearing up the mess the script tries so hard to establish gracefully.

Bateman’s a seriously skillful actor. But with inferior material, his fallback line reading becomes the sardonic, too-cool-for-the-room underreaction, which isn’t the same thing as “milquetoast.” He has the air of a cynical but bored winner, a man fighting his own irritation with everyone around him. That’s not quite right for the figure at the center of “Identity Thief.”

“Identity Thief” is rated R and is showing at College 9 and UEC Theater 12. Visit www.identitythiefmovie.com for more information.