What arguments are there against ranked-choice voting?

Question

In America, most elections are based on first-past-the-post voting, where whoever gets a plurality of the votes wins. For instance if candidate A gets 40% of the vote and each of candidates B and C get 30% of the vote, then candidate A wins, even if 60% of the electorate are steadfastly opposed to candidate A.

This problem can be solved by a system called ranked-choice voting, aka instant-runoff voting, where voters rank candidates from best to worst. Suppose there are six candidates. Then each voter ranks the candidates from 1 to 6. Then the voters's first-choice votes are all tallied up, and whichever candidate gets in 6th place is eliminated, and his voters are reallocated to whoever was their second choice. Once this reallocation is done, the 5th place candidate is eliminated, and this process is repeated until only one candidate is left. (And there are some rules on handling ties, just as there are in the first-past-the-post system.) For more information see here.

Ranked-choice voting has many advantages. It eliminates the concern that third party candidates act as spoilers. And if the Republican primaries had used ranked-choice voting, Trump wouldn't have won the nomination, since a majority of the electorate was against him, it's just that the anti-Trump vote was split.

But my question is, what arguments have been made against ranked-choice voting. It seems like an obviously superior system to me. The only downsides I can think of is that it may be too hard to understand for some voters, and there may be implementation costs. But it's been implemented in San Francisco and several other jurisdictions, and it doesn't seem to have caused any catastrophic problems.

EDIT: My question is not about the difficulties of switching to ranked-choice voting, but about what disadvantages (if any) there are of the system itself.

Answer 1

This problem can be solved by a system called ranked-choice voting, aka instant-runoff voting

First off, there are multiple voting systems based on ranking your choices. The system you're describing is just one example, and it's a pretty bad one, so it's frustrating that people refer to it as "ranked-choice voting", as if it's the only ranked system.

This system is more specifically referred to as "Instant-Runoff Voting". (Though taken literally, there are other systems that use instant runoff rounds, but "IRV" always means this particular system.)

Second, it has a number of problems:

IRV has a spoiler effect

You said:

It eliminates the concern that third party candidates act as spoilers.

It doesn't, though. It actually leads to two-party domination in every country it's adopted in.

It's true that voting honestly for a fringe candidate (Yellow) is safe, since they'll be eliminated immediately and your second choice will go to a mainstream candidate (Green). So IRV is better than plurality in this case (where Red would win even though a majority opposes Red):

However, when the third party candidate becomes more competitive (which is the whole point of adopting an alternative voting system), voting honestly for them takes away votes from your second choice, who will get eliminated first, and then your most-disliked candidate will win in the following round. If the third party hadn't run, your more-preferred candidate would have won, so the third party is acting as a spoiler, and in fact the effect is worse than in plurality (red bar extends further to the right):

(These images are from Voteline)

Video illustration of this effect:

Favorite Betrayal in Plurality and Instant Runoff Voting

Primer also has a great video showing this effect:

Simulating alternate voting systems

These effects have been modeled graphically on 1-dimensional and 2-dimensional political spaces, and produce bizarre win regions where the population moving toward a candidate causes them to lose, and vice versa. In this example, if the population's opinions shifted to the right, reducing support for Red and increasing support for Yellow, it would cause Red to win instead of Green!:

In 2 dimensions, we can see IRV giving the election to Green even when the population is centered exactly on the Yellow candidate. There's also a bizarre Yellow island that's nowhere near the Yellow candidate, and not present in any of the other voting systems pictured.

Approval voting or Condorcet ranking both have results that make sense, with the candidate nearest to the population center winning:

Animated 2D comparison of different systems:

Yee Animations 0.8

IRV excludes moderates

Similar to above, if there are two more-extreme partisan candidates and a moderate/compromise candidate in the middle, the compromise candidate is eliminated early (for not being anyone's first choice), even though they are the best representative of the population as a whole, and a more partisan candidate is elected instead. This is called the "center-squeeze effect".

This is essentially what happened in Burlington Vermont's 2009 election, which led to IRV being repealed. Montroll was in the center relative to the other major candidates, but was eliminated in the 4th round, and a more extreme candidate won, even though Montroll had a higher approval rating than the winner.

Here are the ideal win regions for 14 candidates, with each winning if the population center is nearest to them:

Here's what happens in IRV. All the candidates near the center are eliminated, and only the more extreme fringe candidates can win:

You can also see the center-squeeze effect by measuring the probability distribution of winners along a political spectrum as this 2024 paper did, showing that RCV has a moderating effect compared to FPTP, excluding extremist candidates from winning:

However, if you extend this same metric to include other voting systems, you can see that almost every other system does a better job of electing the most representative candidate, and RCV actually still has a pretty bad center-squeeze effect, with that same divot in the middle:

This effect gets worse the more candidates there are on the ballot, and the more representative they are. More choices and better candidates on the ballot? Under IRV ("Hare"), this leads to worse results:

These two effects lead to political polarization and two-party domination. You can see how IRV skews Australia's House in favor of the two main parties even though 1/4 to 1/3 of the population would prefer third parties (while STV leads to a more proportional Senate):

IRV is not a Condorcet system

In the Burlington election, Montroll was also the Condorcet winner, meaning he would have won against every other candidate in head-to-head elections. The overall preferences of the population were unambiguous:

• Montroll > Kiss > Wright > Smith > Simpson

But IRV is not a Condorcet system; it eliminated Montroll and elected the population's second favorite Kiss instead.

Likewise, in the 2022 Alaska congressional special election, 54% of voters preferred Begich over Peltola, and 61% of voters preferred Begich over Palin, with an unambiguous Condorcet order of

• Begich > Peltola > Palin

Yet because Hare RCV only counts first-choice votes in each round, and Palin and Begich split the Republican vote between them, Begich was eliminated before the others. If Palin had strategically dropped out before the general election, Begich (also Republican) would have won the election, but she acted as a spoiler, causing the Democrat Peltola to win.

If your system doesn't elect the most-liked candidate (the "Utilitarian Winner"), it should at least elect the most-preferred candidate (the "Condorcet Winner"). IRV guarantees neither.

Some argue that although it doesn't guarantee a Condorcet winner, it is still likely to elect one. This may be true in a two-party system with only one or two strong candidates, but in an election with multiple similar candidates, simulations show it to not perform particularly well:

(Performance is similar when measuring the likelihood of electing the "most-liked" candidate.)

IRV enables tyranny of the majority

Here's a (contrived) example:

• Candidate A is loved by 55% of the population, and hated by 45% of the population (55% overall approval rating)
• Candidate B is liked by everyone (85% overall approval rating)

Under IRV, the polarizing Candidate A would win, because they are preferred by a majority, even though the population as a whole would be much happier with Candidate B winning the election.

"Utilitarian" or "consensus" voting systems like Score/Approval choose the candidate with the higher approval rating, which is considered a better outcome by advocates of these systems.

Another way of viewing this is that Candidate A is a great representative of half of the population, while Candidate B is a good representative of the entire population.

Majoritarian voting systems are not as inclusive, leading to adversarial politics, inefficiency, and even civil wars.

2016 election

And if the Republican primaries had used ranked-choice voting, Trump wouldn't have won the nomination, since a majority of the electorate was against him, it's just that the anti-Trump vote was split.

There's not much good data about this, but it's likely that IRV would still have elected Trump:

• "probably really Trump would have been the IRV victor."
• "it's apparent that under ranked voting, Trump would have won with a majority of the votes"

Score or Condorcet voting would likely have elected Sanders or Kasich, as they had the highest approval ratings:

• "Sanders turned out to be the most honestly preferred candidate." .. "We might look at Sanders’ win here as being a “true” Condorcet winner."
• "Score Voting (all primary contenders, all parties): Either Sanders or Kasich would have won."
• "Notice that even though Democrats voted for Clinton, it was Sanders who really was liked by the most Americans. If we didn’t have separate primaries, Sanders could have won."
• "America really chose Sanders and Kasich."

Answer 2

Trump

And if the Republican primaries had used ranked-choice voting, Trump wouldn't have won the nomination, since a majority of the electorate was against him, it's just that the anti-Trump vote was split.

Maybe. However, by the end of the primaries, Donald Trump was winning an absolute majority of the vote. Instant Runoff Voting (IRV) or plurality, an absolute majority is a winner. It's possible that ranked choice would have helped in the early primaries (and Trump would have never achieved the inevitability at the end), but it's by no means guaranteed.

If your goal is getting rid of Trump, then I would suggest getting rid of partisan primaries instead. That could have led to a candidate like John Kasich or Jim Webb winning.

IRV might have helped in the general election. Presumably Jill Stein voters preferred Gary Johnson and Hillary Clinton to Trump. And Clinton voters probably preferred Johnson and Stein to Trump. It's not clear how Johnson voters felt though. Libertarians have traditionally been split on second choice candidates. In any case, IRV is heavily dominated by the first choice. Since Trump and Clinton were the overwhelming first choices, it would have still been mainly between them.

Ranked choice in general

1. Ranked choice ballots are more complicated to fill out. Instead of filling out a single choice, voters have to fill out a list.

2. Ranked choice voting is harder to understand. It's not as obvious why one candidate wins over another.

3. Ranked choice is harder to process. Instead of just counting votes, the system has to count ordered lists.

4. Ranked choice doesn't fix problems with partisanship or oppression of minority groups in favor of majority opinion. But those are common complaints about the current system.

Note that these aren't insurmountable details. In particular, computers make the implementation difficulties much less important. But they are problems with every ranked choice method.

Also note that this doesn't include any of the arguments for ranked choice voting methods. This question only asks for arguments against. Balancing the competing arguments would be more opinion-based.

IRV in particular

Plurality is better than IRV by some criteria. In particular, monotonicity, consistency, and participation. Quick summary, there are tactical reasons to list different orders than one's actual preference.

IRV does not meet the Condorcet criterion. So in a high partisan environment, it tends to devolve into the same choices as plurality voting.

Of course, IRV is also better than plurality voting on some criteria. In fact, every voting system has some criterion on which another voting system is superior. In particular, the Condorcet criterion and Later No Harm are incompatible, so no voting system fulfills both.

Answer 3

Ranked choice voting would increase the amount of time it takes to determine the winner of elections.

Elections in the US are already painfully slow - the very act of taking weeks to determine a winner in some races has contributed to the crisis in confidence of democracy among some fraction of republican voters.

By switching to a more complicated system, election results could be even further delayed. This would cause more people to think the results were rigged. These would be undesirable effects.

Answer 4

A. Big part of an election IS to show a mandate for the winner. To show a mandate, you need to have popularity. Or "absolute preference" for a candidate - " I like candidate XYZ too win".

Ranked voting shows only "relative preference" - "I like candidate XYZ more than ABC" but it could very well be that I dislike both.

Thus a winner of a ranked voting cannot assure the voters that he or she has the mandate to govern.

Edit: another way to look at this, the winner of a rank voting system is the least disliked candidate, while a regular voting produces the most popular winner.

Answer 5

One of the problems with ranked choice is that it not show how much do you like or rate someone.

If some brothers are voting between an spider and a dog to be their pet, if an the arachnophonic kid vote "dog is better than spider", it will have the same meaning than a kid that likes both (but prefer dog) and vote "dog is better than spider".

Answer 6

Any election system is unfair if it has single-member districts. Fair representation can only be achieved with multiple-member districts.

Of course, executive governments are usually single-member. But parliamentary / congress systems with single-member districts can be easily abolished.

Answer 7

This answer is directed at instant runoff voting vis-a-vis multiple round voting, such as systems where a majority of the vote is required to win the final round.

The big virtue of multiple round voting is that it is easier for many voters, in terms of both time expended for candidate research, and conceptual difficulty, to make a first choice pick only, than it is to rank other contenders in a race beyond the first choice candidate.

In a multiple round voting system, if your first choice candidate doesn't win in the first round, you have additional time to research the candidates who remain, knowing that the research is directly relevant to the outcome, without having to have spent a lot of useless time researching second and third priorities in races where it will never come to an "instant runoff" because first choice decisions will end up resolving the race, or where a voter's first choice makes it into the next round.

Thus, the decision on second choice candidates in a second round is likely to be better informed and hence higher in quality, than in an instant runoff voting conceptual "second round".

The downside of having multiple rounds is that often this is framed as a "top two candidates in the first round" make the second round, and when this happens, the candidates who make it into the second round may not accurately reflect the second choices of the voters whose first choice candidates are eliminated.

Answer 8

With situations you outlined, there are some bad assumptions you're making. First, in the scenario where A gets 40% of the vote and B and C get 30% of the vote apiece, you assert that 60% of the population does not approve of candidate A, despite his win. You get this number by adding B and C together. However, this does not mean that B and C attract equal opposition to A. Rather, it means that 60% of the electorate opposes A, but 70% opposes B and 70% opposes C. A first past the post system does not mean that the candidate is disliked by the electorate if he doesn't receive a vote, but rather he was not the first pick. C supporters may lean more towards A, but see C as the better candidate. However, if C dropped out, they still like A more than B. These metrics can't be accounted in a first pass the post system, which does not care about the votes not received, so long as the winner receive the most.

This is true with the assertion that Donald Trump would not win. All we know is that the support of the less successful candidates meant that Donald Trump was not their first pick, as opposed to #NeverTrump. You can only assume that Trump will get a portion of the support of people who still liked him over other candidates.

If we look at the original set up of a 40%/30%/30% split, Candidate A is still likely to win in a First Pass the Post because he only needs to secure 36% of C's support (11% of the total available voters) to win. Where as B would need to secure 70% of C's support (21% of the total available voters). Keep in mind that C's support does not mean disapproval of A or B. It could be B < A < C or A< B < C. In our real world model, You assume that Kasich Supporters would support Cruise before Trump, without taking into account that Kasiche supporters might have stronger feelings of opposition to Cruise than Trump.

So that's just with some math of yours not with your system.

With your system, lets add to the mix of canadates A, B, C the new comers D, and E. If I arrange my ballot so that C < B < A and never rate D and E because I cannot stand either of them (effectively never voting for them), what happens to my vote if A, B, and C are eliminated? Here my vote is never given to a any candidate because I did not choose either. To correct would you require to rate D and E? If so, what if I use my freedom of speech to still choose not to rate D and E and my ballot is thrown out because it is not complete? What if I do cast a vote for a winning candidate in my order, and still refuse to vote D or E... does that discount my vote?

Answer 9

A prime argument against ranked choice voting is - there's nothing particularly wrong with the current voting system. Why change? What could that change bring that we don't have today?

Yes, we had a dismal 2016 presidential election, with two decidedly flawed candidates. Even the third party candidate sucked that year. The 2016 US election was a perfect storm of lousy choices.

That isn't the fault of the voting system. It's the fault of the parties for letting the situation devolve, and the fault of the voters for not demanding better.

Doesn't matter what voting system you have. As long as you have an electorate who is so easily distracted by smokescreens and irrelevant platforms, and doesn't focus on what is important for the future of the nation, you'll get poor results.