Ranked-Choice Voting

In an election with several candidates, there are different ways of determining a winner. In a common method, each voter votes for one candidate, and the winner is whoever gets more votes than any other candidate. This method is simple, and at first glance seems fair. This voting method is called "first-preference plurality" (FPP) or "first past the post". I will show that it has consequences that contribute to the polarization of our country.

A drawback of FPP is the "spoiler effect": a third-party candidate who doesn't get enough votes to win, can nevertheless alter the election results by drawing voters from one of the two major parties. For example, in the 2000 US presidential election, the major candidates were Republican George W. Bush and Democrat Al Gore. Ralph Nader also ran, under the Green Party. Nader was to the left of both Bush and Gore, so almost all Nader voters would have preferred Gore to Bush.

In Florida, Bush received more votes than Gore, but by a margin of less than 600 votes. Nader received almost 100,000 votes in Florida. Most of those voters were devastated to find that by voting for Nader rather than Gore, they ended up electing Bush.

Not surprisingly, where FPP is used, voters learn to vote strategically, casting their vote for a candidate who has a possibility of winning, even if they are not the voter's first choice. This eventually leads to a two-party system, an effect known as Duverger's law.

Some elections use runoffs to ensure that the winner has the support of a majority of voters. Each voter votes for one candidate. If a candidate gets a majority of the votes, they are the winner. If not, the candidate with the smallest number of votes is eliminated, and a runoff election is held with the remaining candidates. This process is repeated until one candidate gets a majority of the votes.

Another method is called ranked-choice voting. Each voter ranks all the candidates with his first choice, second choice, etc. All the first choices are tallied, and if a candidate gets a majority of the votes, they are elected. If not, the lowest vote-getter is eliminated, and the people who voted for that candidate as their first choice, have their ballots counted for their second choice. This process is repeated until a candidate gets a majority of the votes. The outcome is the same as for the runoff method, but without the time and expense of holding multiple elections, because all the necessary information is collected up front. Ranked-choice voting is also known as "instant runoff".

Ranked-choice voting is currently used in some jurisdictions across the US. For more detail on the history of ranked-choice voting in the US, see this Wikipedia entry.

To see how ranked-choice voting can potentially reduce political polarization, consider an example. Warning: this example uses political labels that may be triggering to some readers. Please understand that ranked-choice voting does not favor any particular ideology. Another example could be constructed in which your favorite ideology benefits.

Let's assume that three candidates are running: a liberal, a conservative, and a moderate. Suppose that there are 100 voters who have the following preferences:

• 35 conservative voters prefer the conservative candidate, with second choice moderate
• 31 liberal voters prefer the liberal candidate, with second choice moderate
• 17 moderate/right voters prefer the moderate candidate, with second choice conservative
• 17 moderate/left voters prefer the moderate candidate, with second choice liberal

In a two-party system where the moderates aren't influential in either party, the conservative party selects the conservative candidate, and the liberal party selects the liberal candidate. The conservative candidate gets 35 conservative votes and 17 moderate/right votes, for a total of 52 votes, winning the election.

In a FPP election with three candidates, if each voter votes their first choice, we would have:

• conservative candidate - 35 conservative voters
• Liberal candidate - 31 liberal voters
• Moderate candidate - 34 moderate voters

In ranked-choice, the first round would be the same as FPP, and we would eliminate the candidate who got the least votes, namely the liberal. That sounds bad for the liberals, right? No! In the second round we will have:

• conservative candidate - 35 first-choice votes
• Moderate candidate - 34 first-choice votes, and 31 second-choice votes from liberals

The moderate candidate wins with 65 votes. The liberal candidate could not have won, but the liberals succeeded in blocking the conservative candidate, through their second-choice votes. A divided nation ends up being governed from the middle, instead of from an extreme. I invite the reader to consider this example in light of the US Presidential election of 2024, in which it is said that some people voted for Trump not because they liked him, but because they disliked Harris and had no other viable choice. Giving the voters more choices can improve outcomes.

Note that with FPP, the liberals could achieve the same result as ranked-choice, by throwing their support to the moderate, if they (1) were savvy and (2) had accurate polls. Ranked-choice makes better sense because it removes those two conditions.

Ranked-choice voting can reduce, or even eliminate, the influence of political parties. Each party sets its own rules for choosing a candidate, in a process that gives power to politicians not voters. With ranked-choice voting, we can have many candidates for one office, because the spoiler effect is not an issue,

For those who want a mathematical view, this Veritasium video says that no voting system can satisfy five seemingly reasonable requirements. Still, we can do much better than FPP.

Here are some frequently asked questions about ranked-choice voting, and the answers from the Official Election Site of Alameda County, California:

• Does my vote still count if I vote for the same candidate five times? Yes, your vote will only count once for that candidate. If a voter ranks one candidate as the voter's first, second, third, fourth, and fifth choice, it is the same as if the voter leaves the second, third, fourth, and fifth choice blank.
• Does my vote still count if I only select one choice? Yes. Your vote will count for your one choice.
• In Albany: With Ranked-Choice Voting, to win one of the 3 City Council Seats, a candidate must earn more than 1/4 of the votes. To win one of the 2 Board of Education seats, a candidate must win more than 1/3 of the vote.

This page was last updated on 6 Feb 2025.