It’s truly disheartening that Reese Witherspoon, whose early-career comedies included such witty fare as Alexander Payne’s “Election,” should have sunk to the level of Anne Fletcher’s crass, frantic farce—a distaff riff on the formula of “Midnight Run” that will make you wince even more often than Charles Grodin did in that 1988 movie.

Witherspoon plays Rose Cooper, who’s shown in an idiotic (indeed, horrifying) opening montage literally growing up in the back seat of her cop father’s patrol car; the experience supposedly imbued her with the desire to follow in her revered dad’s footsteps, though the fellow was apparently a complete lunkhead who put his daughter in danger every night. Cut to the present, when by-the-book Cooper, relegated to the evidence room for an unfortunate incident when she tasered a fellow whose alcohol-soaked shirt exploded in flame, is removed from the doghouse by her captain (John Carroll Lynch) for a special assignment: she’s to accompany a federal agent named Jackson (Richard T. Jones) in driving Felipe Riva (Vincent Laresca), the money man of a drug cartel, and his wife Daniella (Sofia Vergara) to Dallas, where he will testify against cartel boss Cortez (Joaquin Cosio).

Naturally things go awry. Armed men attack the house, kill Felipe and Jackson, and send the unlikely duo of Cooper and Danielle—the latter wearing a slinky dress and dragging a heavy suitcase—fleeing for their lives. What follows is a hideously unfunny chain of episodes—short sketches, actually—in which the two slowly bond even as Danielle tries repeatedly to escape. Witherspoon’s default shtick is to be obsessively businesslike and officious, while Vergara’s is to be brassy and Latin-loud. These aren’t characters but caricatures, crude stereotypes that neither actress can do much with except hope that their frenetic will to please will camouflage the pathetic quality of the script.

That’s the work of David Feeney and John Quaintance, both long-time veterans of series TV whose sole previous contribution to features was the latter’s joint writing credits for the abysmal “Aquamarine” and “Material Girls,” and it’s stuffed to the brim with revelations that are supposed to be surprising but aren’t (like the identities of the masked men who burst into the Riva home, which even the densest viewer should guess immediately, or that of one of the ultimate villains, disclosed in the climactic sequence at a Cortez family quinceanera, of all things) and secondary characters thrust into the action arbitrarily and to little effect (Robert Kazinsky as a guy on the lam who becomes Rose’s quasi-romantic interest, or Jim Gaffigan as a farmer in a particularly painful episode).

The only questions that are likely to linger after the final credits—accompanied by abysmally unfunny blooper outtakes—revolve around which of the movie’s skits was worse. Was the bit in which Cooper and Daniella must pretend to be lesbian lovers, or the one where they’re trapped in a redneck bar and must climb through a bathroom window? The sequence when, handcuffed together, they have to try to maneuver a bus loaded with senior citizens through a highway construction zone, or the one where they have to dress in new duds in the aisles of a general store? The bit in which they’re covered in a cloud of cocaine—with predictably effect on Cooper—or the one in which Cooper dresses up as a boy and then is caught in a bathroom stall with Daniella? Whatever answer you might give to such questions is moot, because all of these sketches are terrible, and having them strung together in the semblance of a farcical plot only makes them worse.

Fletcher, never known for her finesse (“Step Up,” “27 Dresses,” “The Proposal,” “The Guilt Trip”) outdoes herself here, apparently doing little besides setting up shots and then letting the stars do their thing. Similarly cinematographer Oliver Stapleton appears merely to have pointed the camera in the right direction and turned it on. There’s no style to anything they do, or to Christophe Beck’s generically upbeat score. Editor Priscilla Nedd Friendly helps out by trimming the footage to well under 90 minutes, but given the quality of the material, that still seems inordinately long.

There have been plenty of rotten buddy-cop movies. Pictures like “The Heat” and now “Hot Pursuit” demonstrate that, unfortunately, men have no monopoly on them.