Chicago mayoral runoff tests Democrats' racial and ideological divides

Brandon Johnson sought to echo Martin Luther King Jr. last week at the biggest rally of the Chicago mayor's race so far, telling a crowd of thousands that the election was an opportunity to "take the progressive movement around the world."

Johnson, the progressive Cook County commissioner, faces moderate former Chicago public schools chief Paul Vallas in the Second City mayoral runoff on Tuesday -- a day that marks the 55th anniversary of King's assassination.