NEW ORLEANS – More than four years after Hurricane Katrina, the single-story brick rancher in Pontchartrain Park where Lisa Perez Jackson grew up stands empty. Floodwaters long ago ate away the walls of her corner bedroom, where the current head of the Environmental Protection Agency once hung Michael Jackson and Prince posters and studied her way to the top of her high school class. Faded spray paint, left by search teams to indicate that no bodies were found, serves as a reminder of the day Jackson evacuated her mother, Marie, to Bossier City ahead of the approaching storm. Katrina was...