Social Science

Tired of voting for politicians? Approve them instead!

A mathematical system called “approval voting” allows voters to cast more than one vote, giving minority candidates a chance in elections

July 14, 2022
Hands of three people. Two people on the left insert a ballot into a box. One person on the right points finger into the box.
Approval voting has been used in some professional societies, such as the Mathematical Association of America, and in some primary mayoral elections in the U.S. [Credit: Arnaud Jaegers | Unsplash License]

It’s 2022: another big year for politics, with midterm elections on the horizon. But as we make our way to the voting booths, we may wonder whether the way we cast our vote today — where a voter can only choose a single candidate in a method known as “plurality voting” — is the only way to elect politicians.

If you ask this question of a mathematician, they might offer some alternatives, including a system called “approval voting.” Instead of the widely-used plurality voting, approval voting allows casting votes for more than one candidate that a voter deems acceptable for the position. 

Each vote weighs the same — unlike in ranked-choice voting, the system used in the New York City mayoral election last year, where voters were asked to rank the available candidates. Technically voters can pick all candidates available on the ballot, but that’s rarely ever the case. “If there are five candidates, the average person would vote for two or three,” says Steven Brams, a political science professor at New York University.

In the United States, voters’ political preference is often seen as binary: either left or right. But approval voting recognizes voters’ political leaning as a spectrum. For example, one can be a moderate conservative, right-leaning voter while tolerating moderately liberal politicians. Studies show that candidates who win approval voting elections are typically relatively moderate and can appeal to both extremes as well as the middle. “The big advantage is electing consensus candidates, rather than extremists who are not representative of the entire electorate,” Brams says.

This new system offers voters a chance to vote for minority candidates without having to worry that they’ve wasted their vote on a candidate who’s unlikely to win, Brams adds. Consequently, minority candidates are given bigger chances in the election without having to fear losing votes to their stronger counterparts. But approval voting can only be applied if there are more than two candidates in an election. While mathematicians also warn of the possibility of multiple ties for candidates approved by the same number of voters, Brams dismisses that: “If approval voting attracts more candidates, which is possible, then [a tie] becomes even more unlikely.”

This approach has been used by scientific and engineering societies to elect respective chairs. The Mathematical Association of America (MAA) was among the first societies to use approval voting in its 1987 internal elections, according to a 1992 paper. The study didn’t specify the reason for MAA’s adoption of the voting system, but the system was approved after a “heated but not acrimonious” debate — as recounted by then-MAA president Lynn Arthur Steen in a correspondence to Brams — and is still used today.

St. Louis on the Mississippi river by night. Jefferson National Expansion Memorial aka. Gateway Arch and Old Courthouse are visible.

St. Louis in Missouri was among the first U.S. cities to use approval voting in its mayoral election in 2021. [Credit: Daniel Schwen | CC BY-SA 4.0]

Outside of scientific societies, Fargo, North Dakota and St. Louis, Missouri are among the first cities to adopt approval voting for mayoral elections, in 2020 and 2021, respectively. In St. Louis two candidates, Tishaura Jones and Cara Spencer, received over 57% and 46% approval, respectively, during the vote in March 2021; Jones eventually won the seat following a runoff a month later. In previous primaries, candidates only won with less than 33% of the vote. “The people of St. Louis have found the solution to unifying their voice. It was simple, it was free,” said Aaron Hamlin, the executive director of the Center for Election Science in a statement.

Several tech workers in Seattle are also interested in bringing the system to the city’s primary election ballots. They filed the initiative to the city of Seattle in late January, arguing this approach would help achieve more representative elections results, as reported by GeekWire. Seattle voters will decide in the election in November whether to pass the initiative.

But there is still a long way to go for voters in Seattle, let alone nationwide, to cast votes on multiple candidates during elections. Critics of the Seattle campaign argue that the approval voting might “suppress the voting power of communities of color.” “Moderates would win the highest ‘approvals’ every time,” critics argue. “The general election would then be a choice between two status quo candidates, sidelining racial justice as an issue and suppressing the voices of Black and brown Seattleites.”

Approval voting in St. Louis is also on the brink of being replaced by another system due to increasing rejection. Those in the opposition, like St. Louis Alderwoman Sharon Tyus who led the move to repeal the system, argue that the system doesn’t allow people to express their political leaning as freely as before.

In the meantime, voters in the U.S. might be stuck with choosing between two candidates from major parties — or, as many people would like to say, “choosing the lesser of two evils.”

About the Author

Kharishar Kahfi

Kharishar Kahfi was born and raised in Indonesia’s capital of Jakarta and has been interested in science and journalism since he was a boy. He combined those interests by reporting on environment and science issues. When not on deadline, he spends time with comics, video games and laundry.


1 Comment

John Whitmer says:

Approval voting – as this well-written article clearly points out – is better than familiar plurality (winner-take-all) voting, not exactly a high bar. I like to imagine how I would approach a ballot with a different format such as approval voting. First, it’s great that I’m not limited to “approving” only a single candidate. However, if I had a candidate I strongly supported, I would be reluctant to “approve” any others as that would dilute the support for my favorite, lowering her chance of winning. So I might be inclined to only approve my favorite and forgo the opportunity to approve other candidates – some of whom I might find quite acceptable. If enough folks do this, approval voting morphs into plurality voting – the very method we are trying to replace.

There is another voting method that allows a fuller expression of voter views without reducing your favorite’s chances of winning. It has all the advantages of approval voting, is more widely used than approval voting, and interest in it is growing nationwide.

Fortunately both ranked-choice voting and approval voting are better than winner-take-all voting. So which ever method you favor, it’ll be an improvement.

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