When we hear one person one vote most people think of the right to vote, but in the United States of America the fight for an equal vote has been a long one, and gaining the right to vote was only the first step.
The U.S. Supreme Court has declared that equality of voting - one person, one vote - means that the "weight and worth of the citizens' votes as nearly as is practicable must be the same."* The astute reader may have noticed that the Supreme Court gave themselves an out with the "as nearly as is practicable" clause, and at the time of this ruling no voting method in use had ever delivered on this ideal, but that has changed.
Traditional "Choose-One" elections only ensure that all voters have an equally weighted vote when there are two candidates in the race. If there are more than two, whichever side runs more candidates is at a serious disadvantage. The majority can end up divided and conquered, splitting support between a few good options and causing both to lose.
*Wesberry v. Sanders, 1964.
"The Spoiler Effect" is when a losing candidate (or "Spoiler") draws enough support away from the candidate who should have won to throw the election.
"Vote-Splitting" is when a faction of voters split their support between multiple candidates on their side. Vote-splitting can leave a majority coalition divided and conquered.
The Current System
Most of us are used to the traditional "Choose-One" Plurality method. Voters vote for one candidate only, and the candidate with the most votes wins. Simple. But while it may sound fair and equal, it is not. For well over 100 years the field of electoral science has been in consensus that the "Choose-One" Plurality method is deeply flawed, is highly gameable, is extremely polarizing, and not only that, election science data and studies consistently show that "Choose-One" Plurality is the least likely to elect the candidate who best represents the will of the people.
Voting for your favorite should be a simple choice, but in the current system voting for your favorite can end up wasting your vote. In RCV voting for your favorite can actually backfire, ironically helping your worst-case scenario win. As a result voters do backflips to try and make sure they have a voice, and strategies like voting for the lesser of two evils are widespread.
But why is "Choose-One" Plurality so bad?
Vote-Splitting and the Equal Vote:
Traditional "Choose-One" voting works great if there are only two candidates in the race. The majority always wins. Easy. But when voters are only allowed to support one candidate, that puts voters who have more than one candidate on their side at a serious disadvantage. A coalition or faction who runs more candidates than the other side risks ending up divided and conquered- in many cases electing a candidate who was opposed by a majority of voters.
Choose One voting has serious vote-splitting any time there are three candidates or more, and even if a third candidate isn't viable at all, they can still split the vote and throw the race if the front-runners are neck and neck.
The examples at the national level are notorious: In 2000, Ralph Nader split the left vote and cost Democrats the presidency. In 1996 Ross Perot split the right vote and cost Republicans the presidency. Both of these candidates were scapegoated, even though the system was to blame, and the resulting backlash dealt a crushing blow to 3rd parties. This isn't just a US problem though. Throughout the world it's been proven time and time again that Choose One Plurality voting results in two party domination as voters learn the hard way that they need to vote for the frontrunners if they want their votes to count.
The Equal Vote = Equitable Outcomes
Studies on the demographics of elected officials in the United States show that white men held 62% of elected offices in 2019, despite comprising only 30 percent of the population. The reasons for this pervasive inequity of representation go back all the way, but in order to change it, we need a new system where new candidates and aspiring politicians can run and win.
In order to achieve gender parity or racial equity in politics, candidates need a level playing field, but the spoiler effect is a glass-ceiling. Voters face strong incentives to carefully study the field and only vote for the candidate on their side who they think can actually win, even if that person is just the lesser of two evils. But further compounding the issue is the fact that who is deemed electable is in large part determined by media bias. Candidates who are well funded, those who have the name recognition, and those who are already in positions of power, are all much more likely to be seen as electable, and to get this strategic voting boost.
The reality is that voting methods which give a strong advantage to those who are deemed most electable will continue to uphold serious disparities in representation, regardless of public opinion.
How can we tell definitively that a voting method provides an equally weighted vote to all voters?
As it has been since ancient times, the test for equality of weight is balance. To determine whether two objects are of equal weight, they must balance when placed on opposite sides of a balance scale.
Any voting method which passes the Test of Balance passes the Equality Criterion and can be said to guarantee an Equally Weighted Vote. In order for a voting method to pass the Test of Balance the ballot must allow voters to give equal support to candidates, and there must be no limit as to the number of candidates a voter can support.
In short, "Any way I vote, you should be able to vote in an equal and opposite fashion." Mark Frohnmeyer, founder of the Equal Vote Coalition.
Passing the Equality Criterion is the key to eliminating vote-splitting and the Spoiler Effect.
Vote-Splitting and Alternative Voting methods:
Ranked Choice Voting, where voters rank candidates in order of preference has been lauded as a solution, but in elections where the third candidate is actually competitive, vote-splitting remains a serious issue.
The issue is in the way the votes are actually counted. RCV works like a series of Choose-One elections where the 1st choice votes are counted and one candidate is eliminated in each round. This works well if your favorite is weak and your vote is quick to transfer, but for voters whose favorite is a strong underdog that isn't eliminated until late in the game, their next choice may never come into play. If your next choice was eliminated before your vote transferred, your ballot may have nowhere to go. One study of 96 recent elections in the USA found that on average over 10% of RCV ballots were not counted in the deciding round of the election. This study and others also showed that historically marginalized communities are more likely to have their ballot not count in RCV. Another study showed that Ranked Choice is expected to lead to spoilers in 15% of competitive elections, or worse if there are more candidates. We can do better.
Luckily, not all voting methods are vulnerable to vote-splitting. As it turns out, voting methods where all ballot data is counted, and where voters are able to show no-preference if they like candidates equally eliminate vote-splitting and pass the Equality Criterion. This includes STAR Voting, Score Voting, Approval Voting, 3-2-1 voting, and many others.
Raising the bar for elections, and mandating that voting methods not play favorites would have massive repercussions; empowering voters to vote their conscience, eliminating wasted votes, making politics less polarized, making campaigns more positive, making it more accessible to run for office, breaking glass-ceilings, and delivering more equitable representation.
Which Voting Methods Definitively Provide an Equal Vote?
Many voting methods eliminate vote-splitting, eliminate spoilers, and ensure an equal vote for every voter, no matter how many candidates are on their side and there are voting methods for every ballot type out there that pass the criterion. Whether voters prefer a 5 star ballot, a ranked ballot, or a traditional looking ballot there's no need to sacrifice the equality of the vote.
In general score voting (cardinal) methods including STAR voting and Approval voting ensure an equal vote. Many Condorcet methods which allow equal rankings, and which count all rankings given, pass the Equal Vote as well. Lastly, a number of hybrid methods including Ranked STAR voting which use a ranked ballot and are tallied using addition pass.
Some voting methods go further and actually guarantee an Equal Vote, assuming that the ballot is not left blank. STAR Voting, which is binary in the final round, guarantees that every vote cast is equally weighted, regardless of the initial scores given. Approval voting also guarantees an equal vote. If Score voting ballots are normalized to ensure that a minimum and maximum score is always given then Score voting also guarantees an equal vote.
Choose-One Plurality Voting (First Past the Post) and Instant Runoff Voting (Ranked Choice Voting) do not satisfy the Equal Vote Criterion.
Any voting method will satisfy the Equality Criterion in elections with two candidates only.