Chris Rock makes his directorial debut with this bracing political satire, in which he plays an inept Washington alderman tapped to run for president. The script is updated Capra: after the Democratic nominee dies, a party bigwig appoints Rock as a sacrificial lamb to go up against the seemingly unbeatable incumbent Republican vice president, who ends every speech with the mantra: "God bless America--and no place else!" Soon the dark-horse candidate finds his own funky voice and emerges as a populist hero, threatening not only the veep but the button pushers in his own party. The gags come fast and furious, and though some are a little stale, Rock and cowriter Ali LeRoi strive for wit over crudity--in a priceless homage to Buster Keaton, reports that Rock will win California send white voters stampeding out of their gated communities toward the polls. 95 min. Burnham Plaza, Century 12 and CineArts 6, City North 14, Crown Village 18, Ford City, Gardens 1-6, Lawndale, Lincoln Village, Norridge, North Riverside, 600 N. Michigan, 62nd & Western, Village North.