In front of roughly 200 supporters gathered at a cold, windy Northerly Island, former U.S. Sen. Carol Moseley Braun formally announced her candidacy for Chicago mayor Saturday. “I just want to serve,” Braun said. “Government is about the people’s business and my life’s work has been dedicated to making government work for all of the people.” In her 24-minute speech, Braun said that opponent Rahm Emanuel’s television ads about Chicago needing to decide whether to be a great city or a second-tier city “pose a completely false choice.” “Chicago will always be a great city, because its people will tolerate...