Rahm Emanuel, who helped elect the first black president of the United States, is one of the toughest SOBs in American politics. And yet it seems the biggest threat he faces to his job as mayor of Chicago is a schoolteacher. But don’t let Karen Lewis’s sing-song telephone voice fool you. As president of the Chicago Teachers Union, she has gone toe-to-toe with the mayor and won. Though Lewis has not announced a 2015 bid, polls already have her teaching his honor a lesson.