St. Louis Unified Primary: A Case Study in Approval Voting
In the landscape of American electoral systems, St. Louis stands as a unique outlier. As of 2024, it is the only city in the United States utilizing a unified primary for government office. This system departs from traditional partisan primaries, allowing voters to support multiple candidates to determine who advances to the final runoff.
Key Facts
- St. Louis is the only U.S. city currently using a unified primary for government offices.
- The system was adopted via Proposition D, passing with 68% voter support in 2020.
- Voters can select multiple candidates in the primary; the top two advance to a runoff.
- St. Louis is exempt from the 2024 Missouri Amendment 7 ban on such systems because it enacted its process in 2020.
- The system has survived two separate repeal attempts by city officials.
The Path to Adoption: STL Approves
The transition to this system was driven by the "STL Approves" campaign. Originally known as St. Louisans for Ranked Choice Voting, the group shifted its focus to approval voting—a system where voters can vote for as many candidates as they find acceptable—combined with a runoff. This change was necessitated by technical limitations, as voting machines in St. Louis and St. Louis County were incompatible with Instant Runoff Voting (IRV).
In April 2020, the campaign gathered sufficient signatures to place the measure on the ballot as Proposition D. The initiative saw overwhelming public support, with polling indicating over 70% approval across all demographic groups and political parties. On election day, the measure passed with 68% of the vote, making St. Louis the first jurisdiction in the United States to adopt this specific model.
[ไม่มีภาพประกอบ]The 2021 Mayoral Election
The first application of the top-two approval primary occurred on March 2, 2021. The primary saw a voter turnout of 44,571 (22.14%), followed by a runoff on April 6, 2021, with a turnout of 57,918 (28.8%).
The election featured four candidates: three Democrats and one Republican. Data showed that the average voter supported 1.56 candidates. This structure fundamentally changed the political dynamics; in a traditional closed primary, the top Democrat and top Republican would typically advance. Under the unified primary, the top two candidates—regardless of party—advance. In a Democrat-majority city, this allows two Democrats to compete in the runoff while giving Republican voters a voice in which Democrat ultimately wins.
| Candidate | Party | Votes of Approval | Approval Percentage |
|---|---|---|---|
| Tishaura Jones | Democratic | 25,388 | 56.96% |
| Cara Spencer | Democratic | 20,659 | 46.35% |
| Lewis E. Reed | Democratic | 17,186 | 38.56% |
| Andrew Jones | Republican | 6,428 | 14.42% |
Legal Challenges and Repeal Attempts
Despite strong public support, the system faced opposition from the city's aldermen. In January 2022, a majority of aldermen attempted to repeal the system and return to partisan primaries. However, repeal required a two-thirds majority, which was not achieved. Shortly thereafter, voters passed Proposition R with 69% support, which mandated that any future changes to the voting system must be decided by a public vote.
Further challenges emerged at the state level. In February 2024, legislation was introduced by Ben Baker to ban approval and ranked-choice voting across Missouri. This culminated in the passage of Missouri Amendment 7 in November 2024. While Amendment 7 prohibits such systems in other parts of the state, St. Louis remains exempt because its system was enacted in 2020, prior to the amendment. Consequently, St. Louis continued to use the system in its 2025 mayoral election.
Frequently Asked Questions
What is a unified primary?
A unified primary is an election system where all candidates, regardless of party affiliation, run in a single primary election. Voters can approve multiple candidates, and the top two finishers advance to a final runoff election.
Why did St. Louis choose approval voting over ranked-choice voting?
The campaign shifted to approval voting because the existing voting machines in St. Louis and St. Louis County were incompatible with the requirements of Instant Runoff Voting (IRV).
How does the unified primary affect party dynamics?
In a majority-party city, it allows multiple candidates from the same party to advance to the runoff. It also encourages candidates to appeal to voters outside their own party to secure a top-two spot, as seen with the incentive for Democrats to present moderate platforms to attract Republican votes.
Is approval voting legal in the rest of Missouri?
No. Following the passage of Missouri Amendment 7 in November 2024, such systems are prohibited in other parts of the state. St. Louis is the only exception because it adopted the system in 2020.
How can the voting system be changed in St. Louis now?
Due to the passage of Proposition R, any further changes to the city's voting system must be put to a public vote rather than being decided solely by the board of aldermen.