The 1983 Chicago Mayoral Election, a Contest between US Rep Harold Washington, and State Representative Bernard Epton in the General, and incumbent Chicago Mayor Jane Byrne plus Cook State attorney Richard M. Daley resulted in the election of Chicago's first African American Mayor—Harold Washington.
Early on in the race, the future mayor was a near non-factor; with Daley leading Byrne in early polls as her administration was widely seen as an incompetent and Petty one that had pushed through unpopular tax raises.
However, Daley—who got a slow start to campaining after announcing—lost ground to Byrne as the mayor began airing ads to portray her as a competent administrator, nearly suceeding if it weren't for Harold Washington entering the race and consolidating the African American vote.
Here, Washington had blindsighted the Chicago Regular Democratic organization and Daley Supporters, as because of both their campaigns, the white vote had been grievously divided.
In fact, Both Byrne and Daley supporters were so blindsighted that IL House Speaker Mike Madigan and US Rep Bill Lipinski Sr both indicated that they were surprised at how their own wards voted.
Nonetheless, Washington won; facing off aggainst State Representative Bernard Epton in the General election in what was a close and bitter contest
Partially as a result of the primary, as well as other reasons, multiple Democratic comitteemen—with one of them privately alleging fraud because of the fact that in some precincts Washington attained around "99.5%" of the vote
In this sense, the Defining theme of this election was racial polarization, with Washington attaining near unanimous support in Black wards, and just as much opposition in White ethnic wards as they were opposed to him becoming the first African American Mayor
To this effect, what tipped the scales in Washington's favor was him attaining 40% of the votes among the Liberal northside lakefront wards, as well as winning hispanics by a healthy margin.
Lastly, in addition to this election resulting in the first african american mayor, it was also a major blow to the chicago machine, as Washington brought multiple new alderman alligned with him, allowing him to diminish the influence of traditional democratic power brokers
In the end, Harold Washington would serve as mayor until his death in November 25, 1987—winning two strong contests that year to remain as mayor.