Who can begrudge the Coen brothers a breather after the slowly strangulating suspense of “No Country for Old Men”? A comedy of persistent idiocy like “Burn After Reading” is a logical, and healthy, response both to the frightening world depicted in their Oscar-winner and to the expectant burden of their mainstream accolades. No classic for old Coen fans, their new film, which arrives in theaters Friday, is nonetheless a perfectly enjoyable yarn. It’s a little like observing mice in tutus and tuxedos scurrying their silly ways through a maze, and, well, you couldn’t ask for better choreographers.

It all begins one day when Princeton old boy Osborne Cox (John Malkovich), a Washington, D.C., CIA analyst and 5-o’clock drinker, is abruptly sacked. He resolves to write a memoir, to the disinterest of his pitiless wife Katie (Tilda Swinton), but then a floppy disk containing his computer’s tell-all contents goes astray. Bopping airhead Chad (rhymes with Brad … Pitt), a health-club trainer, finds it and cooks up a blackmail scheme with frumpy co-worker Linda (Frances McDormand), who’s obsessed with bankrolling a plastic-surgery overhaul.

As Joel Coen has said of the film in his customary deadpan, “The plot concerns the Central Intelligence Agency and the world of physical fitness, and what happens when those two worlds intersect and collide.” Add to that George Clooney’s Harry Pfarrer, an amiably one-track-mind marshal who’s cheating on his wife with Katie. When he also hooks up with Linda via Internet dating, the Washington-Georgetown circle of dimwitted subterfuge is complete, shot with the brothers’ characteristic crispness and set to Carter Burwell’s obliviously bombastic spy-thriller score.

Call it a “league of idiocy” — as does the hilariously dyspeptic Cox. Joel and Ethan Coen’s shaggy-dog but precise screenplay leisurely unspools the increasingly frantic antics of their hapless characters, but the story isn’t predicated on the giddy left-field lunacy of, say, “Raising Arizona.” The Russians who eventually get roped into the picture, after Chad attempts to leverage Cox and gets only a bloody nose, are standard foils compared with the ludicrous demimondes the Coens conjured in “The Big Lebowski.”

Instead, what keeps the movie at a respectable cruise control is the gusto with which the performers infuse their characters, who are forever tunneling to happiness. Linda is absolutely, 100%, without-a-doubt certain that she needs surgically aided butt reduction to stay in the game; passing secrets to a vaguely remembered Evil Empire for cash is merely her ticket there. Harry can’t help rustling up more tail, even if he lacks the wits or the backbone to rebuff Katie, who wants to pin him down for good. Even meek gym manager Ted (Richard Jenkins), who gets stirred into the intrigue later, wistfully sticks to his unrequited pursuit of the oblivious Linda.

Only Chad, who always takes the time to pause and boogie to his iPod, remains buoyant, for a while — as does his hair, a bad blond dye job recalling Mr. Pitt’s early role in “Johnny Suede.” The lexicon of gawp-worthy hairdos in the Coens’ movies — “The Man Who Wasn’t There” even had a barbershop montage — is matched by the colorful rants, tics, and dilly-dallies of their dialogue, which is finely honed here as usual. There’s also, fair warning, a requisite yet surprising bit of violence, though not nasty.

If there’s not much more to tell of “Burn After Reading,” again, it’s because this film is not as primped as the Coens’ typical story. The goofball espionage isn’t far advanced from Theodore J. Flicker’s “The President’s Analyst” (1967), which was revived by Film Forum this summer and which the Coens reference with the shared character name of Kropotkin (much as the screwy hero “The Hudsucker Proxy” was named Norville Barnes, in homage to the Norval Jones of Preston Sturges’s “Miracle of Morgan’s Creek”). But no matter: As “Burn After Reading” toys with its playful little “culture of ethical failure” (in the memorable phrase of this week’s exposé of the Interior Department), there’s relief in the form of harmless farce.