Set in 1930s Mississippi, O Brother, Where Art Thou?, the latest misanthropic flimflam from the Coen brothers, is like an extended ''Three Stooges'' episode featuring an even stupider version of the cast of ''Hee Haw.'' The Coens may be the only filmmakers in history perverse enough to make a movie that's essentially one long goony obvious dumb cracker routine and to give that movie the sunstruck luminosity of an Andrew Wyeth painting.
The ravishing, wide open look of ''O Brother, Where Art Thou?'' is an achievement; so is the magnificent country blues song, ''I Am a Man of Constant Sorrow,'' that's pivotal to the plot. To Joel and Ethan Coen, however, even the occasional dab of beauty is all just part of the joke: The characters are wandering through a back country paradise, and they're such thick skulled hayseeds that they don't even know it.
As Everett, the leader of a trio of chain gang escapees, George Clooney is leeched of his charisma, but then, with a few notable exceptions (''Fargo,'' ''Blood Simple''), turning actors into blustery automatons is what the Coen brothers do. In ''O Brother,'' a redneck kitsch burlesque, they pile on gags about hair pomade, Bible thumpin' prophecy, even the Ku Klux Klan, yet there's such an anvil heavy archness to the whole affair that the effect is stultifying. A riddle for cinema scholars: Why would filmmakers with this much talent work this hard to thumb their noses at everything they put on screen?