With their latest movie, Burn After Reading, the Coen Brothers have disappointingly retreated from the chilly heights of their brilliant Oscar-winning No Country for Old Men and taken refuge in the glib, smartass cynicism that’s been a feature of so many of their movies.

Yet again the Coens parade a carnival of stupidity before us, another cavalcade of caricatured schmucks, imbeciles and idiots to rank alongside the confederacy of dunces that lined up in their 1995 black comedy Fargo – yet without the warmth and humanity of Frances McDormand’s shrewd, heavily pregnant police chief Marge Gunderson in that movie to temper the prevailing mood of sneering misanthropy.

McDormand appears in Burn After Reading too, but her character here has none of Marge’s virtues. Her Linda Litzke is a dim worker in a Washington gym who is desperate to fund the expensive course of extensive plastic surgery she believes will transform her life for the better.

Meanwhile, in the same city but inhabiting a completely different world is another dissatisfied soul: John Malkovich’s Osborne Cox, a prissy, bow-tie-wearing CIA analyst with a drink problem and a lofty disdain for the folly of everyone around him. But he’s not nearly as smart as he thinks he is. His wife, a frosty, patrician doctor played by Tilda Swinton, is having an affair under his nose with George Clooney’s wolfish federal marshal, Harry Pfarrer, while his superiors at work don’t appear to share his high estimation of his own abilities.

The disparate worlds of gym worker and CIA man are unexpectedly yoked together after a computer disc containing Osborne’s sour memoirs of his life in the agency accidentally fall into the hands of Linda and her colleague Chad, a boyishly upbeat twerp with blond streaks in his hair, played with comic gusto by Brad Pitt.

Linda and Chad reckon they can take advantage of this unexpected windfall, but everything goes pear-shaped…

Burn After Reading doesn’t quite go completely pear-shaped itself, but coming directly after No Country for Old Men it’s something of a letdown.

Admittedly, the film does have its good moments. Brad Pitt, playing zanily against type, raises a chuckle or two, and so does J K Simmons’s weary CIA boss (his laconic summary of the whole imbroglio is very funny indeed). But McDormand and Clooney, in particular, mug away furiously with limited comic returns, and the movie’s farcical plot never really gathers momentum.

Yet it’s Burn After Reading’s contempt for its characters that irritates me most. Richard Jenkins, as the gym boss, who nurses a silent crush on Linda, is the nearest there is to a sympathetic individual, but he appears to be regarded with the same derision as everyone else.

I suppose you could try to argue that The Coens are attempting a skewed satire on the arrogant folly of American foreign policy (in the film’s CIA strand), and on the delusional folly of American self-improvement (in the gym strand), but it’s a big stretch. Looking back on the highs and lows of the Coens’ career, I’m beginning to suspect that the brothers, like Malkovich’s Osborne, aren’t quite as smart as they think they are.