The 2023 Chicago Mayoral Election, a contrast between a wide swath of candidates includint Incumbent Mayor Lori Lightfoot, Cook Commisioner Brandon Johnson, superintendent Paul Vallas and Congressman Chuy García saw the defeat of Mayor Lightfoot, and eventual election of Johnson as the City's mayor.
In the first round, Lightfoot lost because of a host of scandals, and perception of mismanaging the city—especially with regards to the perception of violent crimes (which had risen to the COVID-19 Pandemic)—in addition to a host of other scandals such as claiming that she had "the biggest dick in Chicago" (Source)
An 11 day strike organized by the Chicago Teacher's Union—who later endorsed Brandon Johnson—as well as battling the CTU on other fronts such as teacher's work conditions and Covid reopenings
This, in addition to broader discontent among progressives in what was her 2019 Base on the North side, led to her falling behind Paul Vallas (who consolidated the white vote) & Brandon Johnson (who consolidated the progressive vote and bit into her support with the African American vote.
This led to a CTU member (and endorsed) Brandon Johnson and Fraternal Order of Police endorsed Paul Vallas Runoff—Here, the Progressive Johnson and Conservative Vallas presented opposing views for the City of Chicago emblematic of their primary endorsers.
Paul Vallas for example ran a law and order, tough on crime campaign that primarily appealed to the City's conservative white population and allowed him to win the City's Hispanic population. However, the surfacing of an interview where he called himself "more of a republican" likely hurt him among voters.
Brandon Johnson by contrast ran a traditionally progressive campaign; with a twist in that he reached out to various ethnic sectors and tapped into Chicago's black establishment consolidating the African American vote around him in addition to the progressive vote.
In addition to this, thanks to some key endorsement—such as general opponent Jesus Chuy García—he was also able to eat into Vallas' margins among Hispanic voters, preventing the FTOP endorsee from consolidating them and as such playing a key roll in his win.
In the end, the runoff was a story of Racial Polarization, with Johnson landsliding african Americans and Progressive whites, and Vallas winning Conservative whites and Latinos—with Johnson cutting into Vallas' margins with the last group.