New York City voters will also decide the fate of a pair of disgraced Democrats, former congressman Anthony Weiner and ex-governor Eliot Spitzer, whose once-promising political careers were derailed by sex scandals.

Lee Miringoff, director of the Marist Institute for Public Opinion, said de Blasio's success can be attributed to timing, Weiner's demise and doubts about Quinn, who is vying to become the first woman and first openly gay mayor of New York City.