Vote Splitting in the Chicago Mayoral Election—Try Out Alternative Voting Methods!
In the upcoming mayoral election, Chicago’s method of voting puts Black candidates and progressive candidates at a structural disadvantage.
I created an anonymous survey where you can try out voting for Chicago’s next mayor using three alternative voting methods:
https://forms.gle/MrXbFyZJBZcELmtZ6
I made this both as an educational tool to spread awareness about alternatives to our current method, and as an experiment to see if different voting methods yield different outcomes. Please fill out the survey and forward the above link widely so we get a large sample size!
Why alternatives?
In Chicago, we use the same voting method used in most of the country, plurality voting (also called “first past the post”): you only vote for one candidate, and the candidate with the most votes wins.
Plurality voting works great when there are only two candidates running, but if there are more than two, there’s often a problem called vote splitting. Vote splitting is when similar candidates compete for the same subgroup of voters, making it more likely for a dissimilar candidate to win. This can sometimes result in an unpopular, polarizing candidate winning the election without broad popular support.
Fortunately, Chicago adds an additional step: if no candidate reaches a majority, the top two candidates advance to a runoff election. This increases the chance the winner will be broadly popular. However, when there are many candidates running, vote splitting can result in the top two candidates advancing to the runoff with very low levels of support, drawing into question the popular mandate of either finalist.
That is what happened in the 2019 Chicago mayoral election. Lori Lightfoot and Toni Preckwinkle advanced to the runoff, but two thirds of voters (66.5%) didn’t support either candidate in the first round.
It was a historic election: for the first time, both of the top two candidates were Black women, and Lori Lightfoot, who won the runoff with 73.7% of the vote, became the first LGBT Black female mayor of any major U.S. city. But there is a lingering question of how well the outcome really reflected voters’ desires, because both finalists received low support in the first round and the winner subsequently became a polarizing figure.
Perhaps Lightfoot and Preckwinkle really were the most broadly popular candidates; perhaps a large portion of the voters who supported other candidates also liked Lightfoot and/or Preckwinkle, just not as much as the candidates they voted for. But it’s also possible that, with so many candidates competing, the selection of finalists may have been the semi-random result of vote splitting.
Vote splitting may impact this year’s election as well. The 2023 mayoral election has 9 candidates running — fewer than in 2019, but still a crowded field. Seven of the candidates are Black; on one hand, the large number of Black candidates ensures that issues that affect the Black community will get significant attention during the campaign, but because of our plurality voting method, it also makes it more difficult for any individual Black candidate to reach the top two.
Black voters don’t vote monolithically for Black candidates, but Chicago is one of the most segregated cities in the United States; a large proportion of Black voters will want to vote for someone who understands their experience and knows the needs of their communities. Likely those votes will mostly be divided among Black candidates, giving the two non-Black candidates an extra advantage.
Polling already shows this is happening. A poll by Victory Research in late January reported that the two top-polling challengers to Lightfoot were Vallas and García—who happened to be the two non-Black candidates. Vallas polled at 36.8% among White respondents, and García at 43.6% among Latino respondents, but Black respondents were largely divided among Wilson (25.2%), Lightfoot (22.1%), and Johnson (17.8%).
Progressive candidates are also vulnerable to vote splitting this year. The popular Girl I Guess Progressive Voter Guide identifies 4 candidates as progressives. However, two additional candidates have been members of City Council’s Progressive Caucus, so if you include them as progressives too, there are 6 progressive challengers to Lightfoot (who is running as a moderate). In the Victory Research poll, 19.2% supported Lightfoot, 37.4% supported one of the progressive challengers, and 31.2% supported one of the more conservative challengers (Vallas or Wilson). Even though more respondents wanted a progressive challenger, the top polling candidate to challenge Lightfoot in the runoff was relative conservative Paul Vallas (19.5%).
Polling changes all the time, so if you’re voting in Chicago, look up more recent polls before making strategic voting decisions. Keep in mind also that, while vote splitting disadvantages Black and progressive candidates in this election, perhaps in the next election it will be conservatives or Latino candidates who find themselves divided; it all depends on which candidates decide to run. Elections are supposed to be about the will of the people, but the outcome is often determined by the arbitrary mathematics of the pool of candidates.
Alternative voting methods
There are many alternatives to plurality voting that reduce or eliminate vote splitting, but three are currently popular in the United States: approval voting, ranked choice voting, and STAR voting. Each of those methods has a nonprofit organization promoting its use, and each has been the subject of ballot measures for adoption in particular municipalities or states. Each method has its own advantages and disadvantages, but any of them would significantly reduce the frequency of vote splitting. In addition, any of them can eliminate the need for a separate runoff election, which could save governments money.
Approval voting
Approval voting is promoted by The Center for Election Science. It is currently used in two cities: St. Louis, MO and Fargo, ND. The ballot looks the same as with plurality voting, but instead of voting for just one candidate, you can vote for as many as you want. The candidate with the most votes wins, OR the top two advance to a runoff, depending on the local election rules.
Approval voting’s unique advantage is its simplicity. It’s easy, fast, and cheap to implement because it doesn’t require a redesigned ballot or new voting voting machines. In places like Chicago, where we vote on a large number of elected positions (judges, comptroller, Metropolitan Water Reclamation District commissioners, etc.), maintaining a simple ballot design might keep voters from feeling intimidated.
However, approval voting is often criticized for its low expressivity. If you vote for multiple candidates, there’s no way to indicate which candidate is your favorite, which can feel frustrating. Approval voting increases voter satisfaction with election outcomes, but the experience of voting might still feel unsatisfying for engaged voters with nuanced opinions—and American culture strongly values individual self-expression.
Last year, Seattle residents voted on whether to adopt approval voting or ranked choice voting, and 76% of voters chose ranked choice. This might partly be explained by the fact that a movement for ranked choice voting had been present in Seattle for many years, whereas approval voting was newer to the scene. But it might also suggest that many voters find ranked choice voting intuitively more appealing because of its more expressive ballot.
Ranked choice voting
Ranked choice voting is promoted by the organization FairVote. It is currently used statewide in Maine and Alaska and in several cities around the country, including New York City, Minneapolis, and San Francisco. Evanston, IL voted to start using ranked choice voting in 2025.
With ranked-choice voting (also called instant runoff voting), voters rank their top candidates (typically three to five of them) in order of preference. If no candidate receives a majority of first choice votes, the candidate with the lowest number of first choice votes is eliminated and their votes are transferred to other candidates based on voters’ preferences. The process is repeated in successive rounds of elimination until one candidate achieves a majority.
Ranked choice voting’s unique advantage is its familiarity and momentum. It’s the second most common voting method in the U.S., and a lot of people view it as legitimate and well-tested. This can be a huge practical advantage in trying to get it adopted.
However, it is often criticized for not fully solving the problem of vote splitting. The order in which candidates are eliminated is crucial for determining the winner, which sometimes leads to weird situations where voting your honest first choice can help your least favorite candidate win.
One example happened recently in a special election for Alaska’s only U.S. House seat: 60% of voters chose one of the Republican candidates as their first choice, but the progressive Democrat won the election. The moderate Republican candidate could have defeated either candidate in a head-to-head contest, but was eliminated with ranked choice voting.
Such examples might not be common, but they can reduce trust in ranked choice voting and openness to voting reform in general. In this example, vote splitting harmed Republicans, but next time it might harm Democrats—and even in this case, ranked choice voting came very close to electing right-wing candidate Sarah Palin.
STAR voting
STAR voting is promoted by Equal Vote Coalition. It is not yet used in any public elections, but there is a campaign to adopt the method statewide in Oregon.
STAR stands for Score-Then-Automatic-Runoff. Voters rate each candidate on a scale of 0–5. The two top-scoring candidates advance to an automatic runoff where each voter’s full vote goes to whichever finalist they’ve scored higher on their ballot.
A key argument for STAR voting is that it provides the best of both worlds: like approval voting, it reliably prevents vote splitting, and like ranked choice, it provides an expressive ballot. In fact, STAR voting allows voters to express more nuance than ranked choice, since voters can rate every candidate (not just their top 5) and can give candidates equal ratings.
STAR is also the most accurate of these alternatives, performing the best on mathematical simulations. Other methods have some degree of ideological bias: plurality voting has a large center-squeeze effect (candidates at the center are unfairly disadvantaged); ranked choice voting has a moderate center-squeeze effect; approval voting has a slight center-expansion effect (candidates at the center are unfairly advantaged). But STAR voting does not advantage nor disadvantage any ideological position.
However, STAR voting has neither the advantage of simplicity nor the advantage of momentum. It might not be very strategic to try to convince one’s city to adopt a recently-devised method that requires a redesigned ballot and has never been used in real world public elections. That might change in 2024, though, if Oregon voters approve STAR voting for statewide use.
Conclusion
Vote splitting is more rampant in U.S. democracy than many realize. In last year’s elections, the winners of 135 U.S. Congressional primaries won with less than 50% of the vote due to vote splits—including Jonathan Jackson, who won the Democratic primary to replace Bobby Rush in Chicago’s 1st Congressional District with only 28% of the vote. Vote splitting in swing states may have given us two recent U.S. presidents: George W. Bush and Donald Trump. In 2021, vote splitting even enabled a Trump supporter to win a Democratic primary in Massachusetts!
Runoff elections are not enough to temper the fundamental structural flaws of plurality voting. We need an alternative! But which alternative should Chicago choose? The answer depends on the relative importance we place on simplicity, expressiveness, accuracy, and familiarity in consideration of local context. The question of which voting method is best overall is different from the question of which is most politically feasible or appropriate for a particular place.
Is there a practical pathway towards voting reform in Chicago? I don’t know. But the first step is make vote splitting part of the political conversation and spread awareness that alternatives exist. When discussing local political contests, recognize how vote splitting might affect outcomes, and point out that it’s because of Chicago’s use of a flawed, out-dated voting method. A modern city deserves a modern democracy, and we can do better.
(Thank you for reading and don’t forget to fill out the survey!)
