Hurricane Katrina’s third anniversary roughly coincided with the Republican and Democratic national conventions. If the two presidential candidates haven’t talked enough about our national shame in New Orleans, documentary filmmakers are ready to remind them. Spike Lee had his say with HBO’s excellent When the Levees Broke, and this Sundance prize winner, directed by Tia Lessin and Carl Deal, is a worthy companion piece. Seen at SIFF this spring, Trouble has some serious storytelling flaws—a gimmicky before-and-after structure, unclear chronology, people not always identified, crucial information withheld—but a compelling central duo. Kimberly Rivers Roberts and her husband, Scott Roberts, shot the doc’s most harrowing videotape when the two remained in their Lower Ninth Ward home despite the city order to evacuate. (Think The Blair Witch Project with the additional fear of drowning.) Why the hell would anyone stay behind? The Robertses have never been outside New Orleans, it seems. Kim says they “can’t afford to.” Also, there’s the possibility she could take her footage and “sell it to the white folks.” Her raw, frightening hand-held camerawork, with narration by turns profane and pious, is the best thing about the doc, which otherwise interpolates some (too) easy jabs at FEMA and Dubya, none of which is now news. We follow the Robertses off and on through the storm and a year into its aftermath, meeting family members and random strangers. White officials, cops, and National Guardsmen come off the worst. Among the black underclass of New Orleans, the Robertses’ story may not be typical, but their sheer grit, their quintessentially American determination to remain positive and improve their situation, will surely attract notice when this year’s Oscar nominations are announced.