Blondie (Jennifer Jason Leigh) is a creature of the movies: she identifies with the tough persona of Jean Harlow. When her small-time crook boyfriend, Johnny (Dermot Mulroney), pulls a heist in blackface, he’s nabbed by the local black godfather, called Seldom Seen (Harry Belafonte). In a movie-crazy scheme, Blondie kidnaps Carolyn (Miranda Richardson), wife of Henry Stilton (Michael Murphy), a wealthy pol who’s an adviser to FDR. Blondie demands that Henry free Johnny, using his connections in the local Democratic machine. This starts an odyssey through a K.C. kaleidoscope including a home for pregnant black girls, an election with multiple voters, some murders, a blazing jam session at the Hey Hey Club and a shock ending.

Altman loves to explode movie genres, and his script, co-written with Frank Barhydt, fuses the classic ’30s screwball comedy and crime film. Some will say, ““There’s no hero(ine).’’ But Altman sees people as unstable compounds. In Leigh’s gutsiest off-the-cliff performance, Blondie is pathetic, crazy, fearless. Richardson is superb as the repressed, opium-gulping Carolyn, who discovers a gritty reality with her abductor. Belafonte is amazing. Totally transformed from the gorgeous calypsoid icon, he out-godfathers Brando in criminal complexity. He is icy killer, shrewd philosopher of racial reality, hilarious riffing raconteur. It’s a landmark in a legendary career.

The movie’s soul is in the musicians, notable jazzmen like James Carter, Craig Handy, Joshua Redman, Ron Carter, representing figures like Lester Young and Coleman Hawkins. Altman uses them as a Greek chorus to counterpoint the action. No movie in years has used music with such impact. But Altman has already taken heat from jazz critics. Peter Watrous in The New York Times complains that the musicians have no speaking parts, egregiously accusing Altman of using them as ““beasts of burden.’’ But they do have speaking parts: they speak with their saxes, trumpets, basses and drums. Amid the absurdity and corruption that surrounds them, the power and energy of their music is the movie’s image of art and of human possibility.