Departure likely to block Democrats' shot at districtRep. Randy "Duke" Cunningham's announcement that he will not run for re-election next year did nothing to lift the spreading ethical cloud hanging over him, but it lifted a cloud of political angst over the Republican Party and touched off an instant scramble among ambitious Republicans. The Rancho Santa Fe Republican is under investigation by a federal grand jury, the FBI and the U.S. Attorney's Office in Washington over his financial ties to defense contractor Mitchell Wade. In announcing July 14 that he would not seek a ninth term, Cunningham, 63, maintained he...