An unprecedented wave of union support propelled at least four challengers to victory Tuesday over incumbent aldermen backed by Mayor Richard Daley, including veteran Ald. Dorothy Tillman (3rd). But despite a multimillion-dollar infusion of union cash and campaign workers, incumbents Bernard Stone (50th) and Howard Brookins (21st) survived strong challenges in Tuesday's runoff election, with the mayor's help. Labor claimed its most notable victories in the 3rd Ward, where Pat Dowell unseated Tillman, and the 16th Ward, where Joann Thompson easily defeated 16-year council veteran Shirley Coleman. Tillman, a self-styled maverick, had gratefully accepted Daley's help against Dowell, who works...