Embedded Player Tuesday's mayoral election in San Francisco signals the end of an era, as the city's flamboyant mayor, Willie Brown, is forced by term limits to step down after eight years. Brown's centrist, pro-business stance has rankled some liberals in the city, and now several of them are vying for his job. But they could split what pollsters call the progressive vote, ultimately handing the city's top job to Brown's hand-picked successor. NPR's Richard Gonzales reports.