By Ethan Hollander, Wabash College
There are basically three voting systems that are used to elect representatives to public office. The first electoral system is plurality voting, also known as first-past-the-post; the second is the runoff system, sometimes called a two-round system; and the third is the ranked choice or the instant runoff. However, only the first two are widely used.
Plurality Voting
Plurality voting is as simple as: The candidate with the most votes wins.
First-past-the-post is unusual in the sense that it’s not really a majority voting system. Technically speaking, a majority means more than half. However, in this system, one only needs a plurality—more votes than anyone else—in order to win.
Still, first-past-the-post is very common. It’s the system used in the United Kingdom, and as a result it was inherited by a bunch of countries that used to be part of the British Empire, including the United States, Canada, India, Pakistan, and dozens of former British colonies in Africa and the Caribbean.
One reason people like this system is that it’s very straightforward: We only have to do one round of voting, and the candidate with the most votes wins.
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Problems with Plurality Voting
However, the first problem with the first-past-the-post system is the spoiler effect. The spoiler effect is what happens when candidates with similar ideological positions split the vote. Oftentimes, this happens when there’s a minor candidate on the ballot who draws votes away from a major candidate who would otherwise win.
An even bigger problem is that it can be very disproportionate. If one does not need a majority of the votes to win, there’s bound to be cases where the representative for a district is supported by only a minority of the voters.
And the problem is exacerbated when there are a lot of candidates in the race. When that happens, the votes tend to get spread around. So, even the winner sometimes wins with just a fraction of the vote (so long as it’s a bigger fraction than any other candidate).
First-past-the-post is also sensitive to the way that voters are distributed around society. If one political party has a majority—or even just a plurality—across a number of different districts or states, then there’s virtually no limit to how disproportionate the results can be. A party with a tiny plurality in 100 legislative districts could, in theory, win all 100 seats—even though that party represents only a fraction of the electorate.
Factors Affecting Plurality Voting
People get disillusioned when there’s a wide gap between the share of votes in the electorate and the share of seats in the representative body. With first-past-the-post, the party with the most votes wins. The problem is that they sometimes win by a little bit too much.
Geographical luck, strategic games, gerrymandering, even just the surprise performance of a spoiler candidate—all of these elements have an outsized effect in plurality voting. Maybe that’s why dozens of countries, including New Zealand, Australia, and even a few places in the United States—places that used to use plurality voting—have since moved away from it.
Runoff System
The alternative is the runoff system, sometimes called a two-round system, where if no candidate gets a majority, we drop all the other candidates and hold a runoff between the top two.
One of the things that people like about the runoff system is that it provides a way to get around the spoiler effect, which was so common in first-past-the-post.
Remember that in the plurality system, a lot of people who might have preferred one candidate will nevertheless vote strategically for another candidate who they think is more likely to win.
But in a two-round system, we don’t have to do this. We can vote sincerely. We can vote for our favorite candidate, knowing that even if this person doesn’t win in the first round, we’ll still have a chance to choose between the two remaining options in the runoff. One consequence is that third-party candidates and independents do better in the two-round system.
Problems with Runoff System
But, the two-round system has problems of its own.
Probably the biggest is that the two-round system doesn’t eliminate the spoiler effect; it just kind of pushes it back a little.
After all, a runoff system has two winners in the first round—the two people who make it into the runoff. And so, while people might now be willing to vote for the person who’s in third place (in hopes of pushing that person into the runoff), the voter is still in a bind if their preferred candidate appears to be polling fourth.
In other words, we still have a situation where minor parties and candidates might siphon off votes from the major ones. And that puts voters in the uncomfortable position of deciding between voting sincerely (and possibly throwing away their votes) or voting strategically (holding our nose and voting for the candidate we dislike less).
In the end, the runoff system reduces some of the problems with first-past-the-post, but it doesn’t eliminate any of them. And it presents a bit of an inconvenience for voters, who have to schlep to the polls twice instead of once. But unlike first-past-the-post, the runoff system is truly majoritarian—delivering winners who can claim to command majority support, at least in the final round.
Common Questions about Plurality Voting and Runoff System
In plurality voting, the candidate with the most votes wins. It is not really a majority voting system. Here, one only needs a plurality—more votes than anyone else—in order to win.
Geographical luck, strategic games, gerrymandering, even just the surprise performance of a spoiler candidate are some of the things that have an outsized effect in plurality voting.
In the runoff system, sometimes called a two-round system, if no candidate gets a majority, we drop all the other candidates and hold a runoff between the top two.
