"Mr. & Mrs. Smith" is about a marriage in meltdown, about a woman whose husband is leading a disturbing double life and the havoc she wreaks when she discovers his duplicity.

Poor Jennifer Aniston.

Oh, come on. You know that's what you're thinking. "Mr. & Mrs. Smith," starring Brad Pitt and Angelina Jolie, may putatively be a romantic action comedy about a couple of suburb-dwelling hired killers, but for millions of tabloid readers it's the movie that brought Pitt and Jolie together, resulting in Aniston filing for divorce. Of course, Pitt and Jolie's relationship is still a subject of pure speculation, which they've artfully manipulated during the publicity run-up to their movie's opening. But when millions of filmgoers queue up to watch "Mr. & Mrs. Smith" this weekend, it won't be for clever repartee, big explosions or steamy sex (which reportedly has been edited out anyway); it will be to ascertain, firsthand, whether this is a romance of Bogie-and-Bacall proportions or just another Cruise-and-Holmes stunt.

What this critic can report is that Pitt and Jolie create genuine sparks in "Mr. & Mrs. Smith" when the movie gives them the time and space to resemble sentient human beings. And that's a narrow window, indeed. As directed by Doug Liman ("Go," "Swingers"), this hectically paced pastiche seems less interested in exploiting the couple's sophisticated, sexy dynamic than in plunging them into ever more cartoonlike scenes of carnage. What could have been a playful throwback to the banter of the "Thin Man" movies and the derring-do of James Bond instead becomes a live-action episode of "The Itchy and Scratchy Show" from "The Simpsons."

Granted, it's "The Itchy and Scratchy Show" featuring two of the most physically flawless human beings on the planet. As "Mr. & Mrs. Smith" opens, John Smith (Pitt) and Jane Smith (Jolie) are in couples therapy, each facing the camera directly while an off-screen therapist throws them probing questions. As they deliver the quietly devastating answers that will be familiar to anyone who's been married longer than a year, the true purpose of "Mr. & Mrs. Smith" becomes clear: This is a movie about two impossibly attractive mega-stars regarding each other and, in turn, basking in our regard. As long as the audience is okay with that -- as long as they don't go into the theater expecting anything as distracting as a logical story or some kind of emotional arc -- well, then, bring on the extra-large popcorn and let the Big Slurps flow.

And you're gonna need 'em. Clocking in just shy of two hours, "Mr. & Mrs. Smith" will prove a long, hard slog for filmgoers who don't think that simply gazing at Pitt and Jolie constitutes a fun night out. After its promising set-up, the movie takes viewers back in time to when John and Jane first met -- each was, unbeknownst to the other, on a hit job -- through their subsequent marriage and back to the present, where they're living in a well-manicured suburban house with all the modern conveniences. Of course, for Jane, this means a fully appointed arsenal of knives and other weapons hidden in the warming oven; for John, it's a potting shed full of heavy-duty ordnance. The premise of "Mr. & Mrs. Smith" is that these two have gone six years without ever telling each other what they do for a living, which is the first whopper the audience is asked to swallow. The next is that when John and Jane are mistakenly double-booked on a job, they set out to kill each other.

For all its broad physical action and ostensibly hip humor (Vince Vaughn shows up in an uncredited role to deliver the movie's only truly funny lines), "Mr. & Mrs. Smith" is really a meta-movie, one in which we're supposed to snicker at the concept of two glamorous assassins living in the burbs, but in which we're really enjoying the preposterous notion of Pitt and Jolie themselves doing anything as prosaic as arguing about curtains or cooking pot roast. (That last scene, by the way, is just one of several that suffers from weirdly slow pacing.)

Pitt and Jolie throw off unmistakable heat, but little warmth; indeed at times the entire exercise seems creepily cold and calculated. As Jane's attempts to kill John escalate (the joke is that she's the more coldblooded of the two, he still wants to work things out), the similarities to seduction become strenuously apparent; there are enough sex-and-death double-entendres in "Mr. & Mrs. Smith" to make Freud blush. As the movie takes its players into bigger and more bombastic shootouts, featuring bigger and higher-tech gimcrackery, it becomes clear that John and Jane aren't characters as much as props, with their knock-out bodies, extravagantly beautiful faces and great clothes serving as so much set dressing. It's telling -- and appropriate -- that one of the movie's several climaxes involves Pitt and Jolie disguising themselves as mannequins, for that's precisely what they are. This isn't "The War of the Roses," it's "The War of the Poses."

Comparisons with Danny DeVito's toxic 1989 domestic comedy will be inevitable, as will parallels to the great battle-of-the-sexes comedies of Hollywood's Golden Age. But to watch "Mr. & Mrs. Smith," which continually sacrifices its potential for sophisticated fun on the altar of style and physical stunts, is to realize how far we've come from the great movies of, say, George Cukor or Howard Hawks. Those names will mean nothing to Pitt's and Jolie's fans, of course; they barely register now. But some of us would still take those directors' genuinely knowing -- and subversive -- sexual wit over mere physical perfection any day.

Mr. & Mrs. Smith (112 minutes, at area theaters) is rated PG-13 for sequences of violence, intense action, sexual content and brief strong language.

Brad Pitt and Angelina Jolie play husband-and-wife assassins, neither of whom knows what the other does for a living.Angelina Jolie and Brad Pitt give gossip hounds a chance to speculate on their off-screen romance.