Talk:Spoiler effect

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Alternative voting systems which avoid the spoiler effect include instant runoff voting, also known as single transferable vote.

This is wrong on two accounts:

1. IRV and STV are not the same thing. The first is a single-winner system; the second is a multi-winner system. The second reduces to the first in the case of a single district.
2. IRV and STV can suffer from the spoiler effect. For example, if the "p-ist" vote was split between 3 p-ists, the most popular and "major party" p-ist could be eliminated early, even though they would handily beat the winning q-ist.

IRV & Spoiler Effect

IRV is free from the spoiler effect, if implemented correctly, because it meets the Independence of Clones Criterion (ICC). See: [1]

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I've read many other places that IRV only stops the spoiler effect when the third party is weak. In the scenario where the third party becomes almost an equal, the spoiler effect can come back into play. For example if Nader was looking like he might be almost an equal with Bush and Kerry, and we were under IRV, liberals might be afraid to vote for Nader because if it was a runoff between Bush and Nader it would seem more likely that those who ranked Kerry first instead of Nader would put Bush second.

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IRV isn't free from the spoiler effect at all. In order to be "free" from the spoiler effect, it would have to be free from Independence from Irrelevant Alternatives Criterion (IIAC). It's not. It's not even compliant with relaxed versions of IIAC, such as Local IIAC. --- RobLa 03:51, 12 May 2004 (UTC)

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12-17-07: I disagree somewhat with RobLa's claim that freedom from spoiling requires independence from irrelevant alternatives. Suppose candidates can withdraw from contention after election day, that the votes are published at the end of election day, and that withdrawn candidates are deleted from the votes before calculating the winner. If Nader by not withdrawing would elect Bush, and by withdrawing would elect Gore, Nader would have an incentive to withdraw and not be a spoiler. (Nader's supporters who prefer Gore over Bush would bang on his door until he withdraws. In 2000, Nader admitted that Gore was the "lesser of evils.") Candidates who choose not to run out of fear of being a spoiler would no longer have that fear.

A huge part of the "spoiler problem" is that some potential candidates choose not to run. For example, in 2000 John McCain chose not to run (as an Independent) in the US presidential election after the Republicans nominated George Bush, because he knew Gore would win if McCain and Bush both ran. (McCain and McCain's supporters preferred Bush over Gore.) One cannot measure the spoiler effect by considering only the votes and the candidates on the ballot. (By the way, McCain was probably a Condorcet winner in 2000. Most of Gore's supporters preferred McCain over Bush, and most of Bush's supporters preferred McCain over Gore, and a significant number of voters thought McCain was better than both Gore and Bush.)

I agree IRV has a serious spoiler problem and that IRV would maintain the "two big party, each party nominating one candidate per office" system, would tend to defeat centrists by squeezing them between a candidate to their left and a candidate to their right, would therefore deter candidates and parties from taking moderate positions on the issues, and would therefore continue the polarization we've seen under plurality rule. For instance, the Democrats would not nominate both Obama and Clinton under IRV because that could easily elect the Republican:

    30%       17%        8%        45%
  Obama     Clinton   Clinton    Romney
  Clinton   Obama     Romney       x        (x = doesn't affect
  Romney    Romney    Obama        x             the example)

  IRV begins by eliminating Clinton, who was ranked top by 
  only 25% (17% + 8%) of the voters.  Then IRV counts 8% more
  for Romney, giving him a majority (45% + 8%).  If Obama had not
  run then IRV would give Clinton a majority (30% + 17% + 8%).  
  Since Obama's supporters prefer Clinton over Romney, this is 
  classic spoiling.

The official book on Robert's Rules has a section on IRV. The book's authors call IRV by the generic name "preferential voting," a hint they were unaware other preference order voting methods exist. They wrote IRV is better than plurality rule, which should not be considered a strong endorsement. They point out that IRV can defeat the best compromise, which is the same as saying IRV is susceptible to spoiling. Presumably, if they had been aware of Condorcetian voting methods they would have endorsed one of those, since Condorcetian methods are better at electing the best compromise.

IRV can be patched fairly well by allowing the candidates to withdraw after the votes are cast, as described above. In the example, Obama would choose to withdraw in order to defeat Romney and elect Clinton. The Democrats and Republicans would presumably decide to stop spending money on primary elections and would nominate more than one candidate per office. Candidates who want to win would recognize that the way to win is to adopt moderate positions on the issues to try to appear to be the best compromise. With many candidates competing to be the best compromise, voters would be free to rank the less corrupt of them over the more corrupt.

I'm not a fan of plain IRV. I much prefer Condorcetian voting methods. However, I cheerfully acknowledge that if IRV is patched to allow withdrawal then it would be nearly as good as Condorcetian methods.

Condorcetian methods that allow withdrawal would be even better. It would then be a waste of effort to organize voting strategies hoping to manufacture a majority cycle that elects the strategizing voters' preferred candidate, since the "patsy" candidate--the candidate strategically raised over the sincere winner--would have a strong incentive to withdraw. I believe strategic voting would be rare, given the option to withdraw and assuming a good underlying voting method. I believe candidate withdrawals would be rare if the underlying voting method elects within the top cycle and is independent of clones. (For an example of such a voting method, google Maximize Affirmed Majorities.) --Steve Eppley

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—Preceding unsigned comment added by 171.159.64.10 (talk) 02:56, 18 December 2007 (UTC)

Stupid question

I always knew this as vote splitting. How is it different? (add an explanation if it is, add to the merger if not) 142.177.168.90 14:15, 18 Jun 2004 (UTC)

Yes, this should be merged with vote splitting. However, it should not be merged with Independence of Irrelevant Alternatives - the two are related but different subjects.

I would disagree that they should be merged.

First, I believe it would be accurate to say that Vote Splitting is related to the Independence of Clones Criterion (http://condorcet.org/emr/criteria.shtml).

The spoiler effect can refer to either independence of irrelevant alternatives and Vote Splitting and I have seen the terminology used in both contexts.

In the case of independence of irrelevant alternatives, one can think of candidate B as a spoiler for candidate A if, when candidate B was removed, candidate A wins the election.

The situation is different when it comes to clones/vote splitting. If candidate B & A split their votes, it does not imply that either candidate would win the election.

Ericgorr 23:09, 10 Nov 2004 (UTC)

In that case, should the spoiler effect article be a disambiguation page? Tim Ivorson 13:35, 11 Nov 2004 (UTC)

ERRRR , NOPE, Vote Splitting is the action, and the result of this action is the effect of a Spoiler. The Spoiler Effect does not occur until after the voting is finished. If similar candidates read the pre-election polls correctly ; then vote splitting can be avoided and the effect does not occur. Vote Splitting is the egg, comes first, and the Spoiler Effect is the chicken, comes after. Maintain separate pages. - Trinbago

Trinbago is wrong to say the spoiler effect occurs after the voting. Some potential candidates choose not to compete because they expect they will spoil the election. See the example above regarding McCain choosing not to compete as an independent in 2000 after the Republican party nominated Bush. This is an effect that can't be observed merely by counting the votes to check whether any of the candidates who did compete is a spoiler. SEppley (talk) 11:18, 27 March 2012 (UTC)

With some voting methods, such as plurality rule or runoff, vote splitting is what causes spoiling. Other kinds of voting methods have different kinds of votes that cause spoiling. At least, I would call it a different kind with a preference order voting method when most of candidate x's supporters rank x over y and y over z, the winner is z, and y would have won if x had not been on the ballot. Preference order votes can be tallied in different ways by different preference order voting methods, and x>y>z might not cause y to lose and z to win if tallied by a different method. I also call it spoiling when the best compromise (maybe y) chooses not to compete to avoid being made to appear unpopular by the voting method when s/he expects the voting method (e.g., Instant Runoff) will take away his/her victory by counting votes for other candidates (maybe x & z) that would have been counted for him/her by another voting method. The best compromise can easily be sandwiched between a candidate on the left and a candidate on the right and thus lose, when s/he would have won if either the candidate on the left or the candidate on the right had not run or if the voting method tallied the votes in a different way. Since candidates who want to win take positions that will help them win, the spoiling effect causes politicians to avoid taking compromise positions that would result in being sandwiched between other candidates, and this causes polarization. It's an effect of spoiling that you can't measure merely by counting votes. Don't believe people who claim their favorite voting method rarely has spoiling, when they base their claim on the votes in actual elections and ignore candidates who chose not to run and ignore the positions that the politicians chose in order to win. SEppley (talk) 11:56, 27 March 2012 (UTC)

Discussion of Mathematical Definition

I think that the "spoiler effect" is better understood as sensitivity to irrelevant alternatives rather than sensitivity to clones in the form of vote splitting. Given that, Condorcet methods reduce the spoiler effect by only being sensitive to IA's when there is no CW, and approval arguably eliminates the spoiler effect under certain assumptions. --Hermitage 06:33, 14 July 2005 (UTC)

Hmm, it seems to me that violations of IIA can be broken into two distinct scenarios: the "spoiler effect" and the "center squeeze" effect. As the article states, the "spoiler effect" is typically reserved for irrelevant alternatives with weak core support (few number of first choices), as in the Nader scenario. The "center squeeze" occurs when the irrelevant alternative has strong core support (large number of first choices). That's why IRV is typically said to eliminate the "spoiler effect" but not the "center squeeze". Would it be better to say that the "spoiler effect" corresponds to violations of the mutual majority criterion? That is, a "spoiler" is an irrelevant alternative who is partitioned into the "mutual minority" by a majority of voters? The difficulty here is that "spoiler effect" is quite a colloquial term, a possible "neologism" as suggested below, and tough to assign a mathematical definition to. --Progressnerd (talk) 19:15, 11 April 2008 (UTC)

I have two criticisms of Progressnerd's points above. (1) If "spoiler effect" and "center squeeze" are the only ways to violate IIA, which of those classifications covers the Borda clone effect? With Borda, x will win when enough similar inferior alternatives are also nominated, since Borda will give x extra points from all voters and only give its competitor y extra points from the voters who prefer y over x. I wouldn't call this spoiling because the voters who rank the extra candidates over y prefer the new winner x over y. It's clearly not some kind of "vote splitting." (2) It's easy to construct a "center squeeze" example where IRV defeats a candidate with the greatest "core" support: 5 candidates FarLeft, Left, Center, Right, and FarRight. IRV eliminates FarLeft and FarRight first and second, and then counts FarLeft's core support for Left and counts FarRight's core support for Right, so that IRV eliminates Center third.) I also note that core support can't be measured by votes alone, since it depends on info not in the votes, such as which candidates chose not to compete. IRV will count the "core" supporters of candidates who didn't compete for candidates who do compete. Also, core support itself may depend on the voting method: After decades in which plurality rule and top two runoff have caused politicians to avoid taking compromise positions in order to avoid being squeezed into defeat--see the model in which there are only two candidates and both know a third candidate can enter the race and would enter if s/he can take a winning position--voters who follow have been led away from compromise positions they might prefer the most, and they could be led back. SEppley (talk) 12:57, 27 March 2012 (UTC)

Another thought. IIA says that the addition of a candidate that does not win should not be able to change the winner, but that's not exactly what "spoiler" means colloquially. "Spoiler" refers to someone who does not have a chance of winning. Clearly, in the "center squeeze" scenario of IRV, the two candidates with the most first choices are better positioned than anyone to win. The addition of one of those candidates may change the outcome even though that candidate loses, but I don't think that candidate can be considered a "spoiler", because s/he had a legitimate chance at winning. Moreover, it would be silly not to consider Condorcet as eliminating the "spoiler effect" even though it technically does not satisfy IIA. Given that, which irrelevant alternatives are "spoilers" and which are not? --Progressnerd (talk) 15:50, 12 April 2008 (UTC)

Whether or not spoiling has a colloquial meaning shouldn't deter us from generalizing it to cover voting methods with which people have little experience, since its colloquial meaning would surely evolve after people gain experience with other voting methods. The interpretation that spoiler refers only to a candidate who has no chance to win has been induced by our use of "vote-for-one" plurality rule, which causes most voters who prefer a third candidate to abandon their support of the third candidate when they expect only two other candidates have a chance to win. Abandonment is a good strategy when voters can't coordinate their preferences into a winning coalition, but an abandoned candidate, made a "sure loser" by plurality rule, may actually be preferred over the winner by a majority of the voters. Also, the term is often used in a different way to describe candidates who choose not to compete because they don't want to spoil the election. Consider John McCain in 2000 after the Republicans nominated Bush. When asked whether he would run as an independent, he said that would help Gore win and he didn't want to be a spoiler. If McCain had run and changed the winner to Gore, would you call McCain a spoiler? I don't think he fits the "sure loser" description. McCain might have beaten Gore if Bush hadn't competed, so in that sense he did have a chance to win, and with another voting method he might have won (neglecting the important effect that another voting method could have led to different candidates competing, and candidates taking different positions than they actually did). McCain and his supporters thought he would have beaten Gore if Bush hadn't been nominated. So did Rod Kiwiet of Caltech when I suggested to him in 2004 that McCain was probably a Condorcet winner in 2000: Rod agreed that most Bush supporters preferred McCain over Gore, most Gore supporters preferred McCain over Bush, and McCain would have been ranked over both Bush and Gore by many Republicans and "swing voters." SEppley (talk) 12:57, 27 March 2012 (UTC)

Removed redirect from "Split Vote"

Just letting y'all know: I removed the redirect from "Split Vote", since that and "vote splitting" aren't the same thing, though they might sound similar. --DewiMorgan 04:29, 18 July 2007 (UTC)

Spoiler (sports)

Spoiler (sports) redirects here. There is nothing said about sports. 141.151.79.241 22:56, 30 September 2007 (UTC)

Worldwide View

Somebody added the note "does not represent a worldwide view". I disagree. The Bush/Gore example is from the U.S., but there's also a South Korean example. I would vote to remove the note. Jrvz (talk) 01:52, 30 November 2007 (UTC)

Is the article title appropriate?

Where does the term "Spoiler effect" originate from? Is it verifiable? It seems like it might be a "neologism"

Also, as I understand it, "vote splitting" is the mechanism that causes the "Spoiler effect". So "spoiler effect" is a subset of "vote splitting". So shouldn't "Spoiler effect" redirect to "vote splitting"? The way it is now, "vote splitting" redirects to "Spoiler effect"; however, a minor amount of vote splitting will not be sufficient to cause a "Spoiler effect". So this is confusing for the redirected readers.

The term "Spoiler" almost universally refers to a weak or minor candidate in a plurality election who gets relatively few votes but none the less has a "detrimental" or "spoiling" effect on the election outcome. "vote-splitting" is a broader concept that can also involve viable candidates who are similar, and may each receive a substantial percentage of the vote, but allow a dissimilar candidate to win with a mere plurality. The term "spoiler effect" is inappropriate and is not commonly used when there is not an obvious weak "spoiler" candidate. I think the connection between the two concepts should be discussed, but also it should be clear that vote-splitting can happen where there is no "spoiler effect."

Tbouricius (talk) 18:28, 11 April 2008 (UTC)

Mikiemike (talk) 09:09, 1 February 2008 (UTC)--

I agree. Have spoiler effect redirect to vote splitting, rather than the other way around. --Helenalex (talk) 03:41, 13 May 2008 (UTC)

I too agree there should be an article titled "vote splitting". Yet I am in favor of keeping this "spoiler effect" article too.

Already there is a redirect for the hyphenated words "vote-splitting", and that should remain, and point to "vote splitting". For grammatical correctness the article title of "vote splitting" should not have a hyphen. (Clarification: If the title were "vote-splitting effect", then a hyphen would be needed to indicate that the two nouns are being used together as an adjective.)

As I recall the information about vote splitting originally was added to an article named "strategic nomination" which is yet another related concept that also deserves a separate article. Instead of being bounced around as if it were subordinate to voting concepts that would not happen without vote splitting, "vote splitting" needs an article of its own.

When it is added, be sure to change links that now point to the "vote splitting" section of this article, and links that point to the hyphenated "vote-splitting" stub. VoteFair (talk) 22:08, 14 May 2008 (UTC)

I'm not convinced that 'spoiler effect' needs its own page. Are there ever situations in which the spoiler effect is not the result of vote splitting? --Helenalex (talk) 23:52, 14 May 2008 (UTC)

Although I can't think of a case where vote splitting is not one of the contributing causes of the spoiler effect, there can be additional contributing causes to the spoiler effect. For instance strategic nomination may also be involved (especially in U.S. primary elections).

In broader terms, the fact that one concept can be the cause of different effects doesn't imply that all the effects should be fully explained in the same article as the cause. VoteFair (talk) 07:22, 16 May 2008 (UTC)

Fair enough. This page should be rewritten to just be about the spoiler effect, and vote splitting should get its own page. --Helenalex (talk) 11:23, 16 May 2008 (UTC)

I've created a new page for Vote splitting, but it needs work from someone who knows more about political theory than I do. --Helenalex (talk) 08:19, 3 June 2008 (UTC)

Thanks! I've made some refinements to the new article. I'll let someone else decide what, if anything, to remove from the vote splitting section in this spoiler effect article. VoteFair (talk) 20:59, 6 June 2008 (UTC)

TR or Taft?

In the 1912, Theodore Roosevelt had a much better chance than William Taft. Couldn't it be argued that Taft had the spoiler effect? I know that the Progressive, or "Bull-Moose" party was considered more of a third party than Taft's Republican party, but still, I don't agree with how it looks now. —Preceding unsigned comment added by 69.228.15.32 (talk) 01:57, 26 August 2009 (UTC)

Copy edit

I've partially completed copy-editing the article. I've tried to use language that's more readily understood by a lay-person. I've reformatted the list into a table. I added some references where I could find them. I removed a quote attributed to Ralph Nader, because it had no reference and I could not find any source online for it, so it is unverifiable material and has to be removed per WP:BLP guidelines. I will finish copy-editing it later today. // ⌘macwhiz (talk) 17:31, 30 August 2010 (UTC)

Perot?

Where is Perot? He won Clinton the White House in two consecutive terms then disappeared forever. Where is the discussion on candidates planting a spoiler to ensure their win (as Clinton obviously did with Perot)? 198.209.0.252 (talk) 13:42, 21 April 2011 (UTC)

I also wondered why there was no mention of Ross Perot when I read this article. To add him, you would need a reliable source describing him as a spoiler or claiming that he cost Bush the election (all the candidates from that election are still alive). here is an article by Dan Quayle in which he claims Perot gave Clinton the election. here is another article claiming that Perot voters would have split evenly between Clinton and Bush, but without out any reference to a poll to back up the claim, though this may have been a further result from exit polls by Voter Research and Surveys mentioned earlier in the article. (Both articles are referenced in the Wikipedia article on Ross Perot's 1992 campaign.) Not really enough evidence for me to add Perot to the list of spoilers, though better evidence may exist.--Wikimedes (talk) 20:03, 27 August 2011 (UTC)

Nader must be a Millennial thing because Perot was a much more significant force, in the elections of the last 59 years. However, the whole concept of a spoiler is an antidemocratic conspiracy that demands the electorate vote for candidates who identify within the binary party system which has evolved to today's Republicans and Democrats. To say that any spoiler exists is to say that the two party system is threatened by voters who insist on their right to vote for whom they choose. Oh the humanity! CredibleSources (talk) 12:55, 2 November 2019 (UTC)

The frequent "Perot spoiler" claims are always funny because in 1992, Perot was the only candidate who wasn't a spoiler. Perot was the majority-winner (as he would have beat either Clinton or HW in a one-on-one election), so HW was a spoiler. (If he'd dropped out, Perot would've defeated Clinton.) Closed Limelike Curves (talk) 18:07, 5 April 2024 (UTC)

Erroneous claim that ranking moderately left-wing candidate second will minimize chance of electing right-wing candidate?

The article says the following: For example, voters for a very left-wing candidate might select a moderately left-wing candidate as their second choice, thus minimizing the chances that their vote will result in the election of a right-wing candidate. Seems to me there are scenarios in which, depending on the voting method, minimizing the chance that the right-wing candidate will be elected requires ranking a more centrist candidate ahead of the moderately left-wing candidate. Consider an example with 4 candidates: VeryLeft, Left, Center, and Right. Abbreviate VL, L, C and R. Assume the voting method is Instant Runoff. The article stipulated that VL is a very minor candidate, so we assume Instant Runoff eliminates VL immediately. Then C can easily be sandwiched between L and R, so we'll assume Instant Runoff eliminates C next. R will have a much better chance in the final count against L than against C, since the votes that had been counted for C are likely to split between R and L, whereas L's votes would mostly go to C if L were deleted instead of C. So, the claim about minimizing R's chance seems bogus. It should be rewritten or deleted. SEppley (talk) 01:24, 13 March 2012 (UTC)

Spoilers also occur in primary elections & non-partisan elections

Currently this article focuses on spoiler candidates in cross-party (especially U.S. "general") elections (where each party offers only one candidate), and excludes -- in the opening definition -- U.S. primary elections (where all the candidates are from the same party) and non-partisan elections (where the candidates are not associated with parties). Vote-splitting in U.S. primary elections happens far more often than in U.S. general elections. (After all, the reason primary elections arose is to eliminate vote splitting and spoiler candidates in general elections, and that shifted the vote-splitting/spoiler problem to primary elections.) Also, other countries that do not use primary and "general" elections also have spoiler candidates in (some of) their elections. VoteFair (talk) 19:30, 28 March 2012 (UTC)

Gary Johnson

There is no mathematical way that Gary Johnson could have spoiled the election for Mitt Romney due to the Electoral College. I am taking the initiative and removing his name. — Preceding unsigned comment added by 71.198.123.72 (talk) 08:24, 14 May 2013 (UTC)

Reasoning for Stein on the list?

Why is the reasoning for Jill Stein being on the list not in the article? What is the reasoning? jrun (talk) 03:51, 1 February 2017 (UTC)

Table of alleged spoilers

I have removed the table of alleged spoilers from the article for reasons stated below. The solution for putting such information back in the article is also stated below. But first, here is the deleted table for easy reference

Spoiler candidate	Election	"Denied victory" to	Winning candidate
James Birney	1844	Henry Clay	James Knox Polk
Martin van Buren	1848	Lewis Cass	Zachary Taylor
John St. John	1884	James G. Blaine	Grover Cleveland
James B. Weaver	1892	Benjamin Harrison	Grover Cleveland
William Howard Taft	1912	Theodore Roosevelt	Woodrow Wilson
Ralph Nader	2000	Al Gore	George W. Bush
Gary Johnson Jill Stein	2016	Hillary Clinton	Donald Trump

There are two problems with this table. The first is that the table lacks citation to reliable sources. The second is that the table declares frequently disputed facts in WP:Wikivoice. Before restoring this table, it needs to pass both WP:Verification and WP:Neutrality and the best way to do this is to WP:Attribute the analysis and conclusion to the person or group the RS says is making the analysis or conclusion. We'd also need to include disputing viewpoints found in the RSs. Once we do all that, it becomes dubious that a simple table is really capable of passing muster, but I'll reserve judgment until some tweaks are proposed. NewsAndEventsGuy (talk) 13:17, 5 February 2018 (UTC)

Strom Thurmond and Tulsi Gabbard

write here — Preceding unsigned comment added by T Magierowski (talk • contribs) 19:57, 16 December 2019 (UTC)

Theodore Roosevelt's Progressive Party is listed as centre-left to left-wing even if it originated from the Republican Party which is currently considered to be positioned on the right of the Democratic Party. Abraham Lincoln, who was the first Republican President, was progressive by supporting minority rights in similar fashion to future Democrats like Lyndon B Johnson and Barack Obama. Democrat Franklin Roosevelt is considered to be the legacy of Theodore Roosevelt due to his policies rather than his surname which was the same due to them being distant cousins. Republicans became the conservative party that they are known to be today as a result of William Taft's presidency which preceded Strom Thurmond's candidacy in 1948. Franklin Roosevelt's presidency which paved the way for Truman's that allowed Democrats to hold the White House for two decades was defined by Keynesian economics that are considered to be more left-wing than Friedman whose ideas influenced Reagan's domestic policy which limited the state as well as the neoconservative foreign policy of the Bushes.

Strom Thurmond was far-right and his Democratic origins are due to segregationists like Buchanan and Johnson rather than Franklin Roosevelt and Harry Truman who were more distant to Dixiecrats than William Taft. Tulsi Gabbard's non-interventionism has bipartisan support and is endorsed by Trump on the right and Obama and Sanders on the left rather than Romney and the Clintons who are closer to the centre. So if Trump is impeached and replaced by Romney in the Republican ticket, his disgruntled supporters could endorse Sanders, Warren, Yang and Gabbard that are more left-wing than centrists such as Bloomberg and Hillary Clinton and then Tulsi Gabbard's potential run as a third party candidate could help Romney beat Hillary Clinton or Bloomberg so that Vladimir Putin does not take the blame for the third World War that Romney is going to start. But regardless of foreign policy, Taft being a right-wing candidate who spoiled Theodore Roosevelt's presidential run against capitalist non-interventionist Woodrow Wilson whose reaction to the first World War paved the way for the second reminds me of Ron Paul's libertarians accusing Romney of being the same as Obama in 2012. I believe Hillary's loss in 2016 was Obama's and Trump could not win any other election. — Preceding unsigned comment added by 2A02:587:3A0F:5F00:E067:2638:DFC1:10B2 (talk) 20:31, 16 December 2019 (UTC)

You cannot base anything only on "I think". You have to back it up with a source. On Thurmond I could not find anything on him being a spoiler candidate on the Republicans and Gabbard... wait until after November 3rd 2020 and a try finding a source that states that. And I really don't understand what World War III, Mitt Romney, Bloomberg, the Democrat 2020 lot, Buchanan, Johnson or early 20th US politics have to do with whether or not Gabbard and Thurmond are spoiler candidates. Let's stay on topic. Tomasz Magierowski (talk) 20:49, 16 December 2019 (UTC)

https://www.newyorker.com/news/news-desk/the-g-o-p-s-dixiecrat-problem — Preceding unsigned comment added by 2A02:587:3A0F:5F00:E067:2638:DFC1:10B2 (talk) 21:11, 16 December 2019 (UTC)

Once again, nothing to do with Strom Thurmond being a spoiler candidate for the Republicans. Tomasz Magierowski (talk) 21:18, 16 December 2019 (UTC)

https://www.foxnews.com/story/dixiecrats-1948-loss-ushered-in-new-era

Article states that Thurmond's victories in southern states encouraged their shirt from Democratic to Republican but I believe it was a result of Taft's conservatism rather than the Dixiecrats. World War 2 empowered Roosevelt and no one was able to challenge the only president to serve more than two terms in office but Truman was expected to lose against Dewey and the 1948 election was one of the biggest failures of the polls that are referenced in this article. Thurmond's emergence as Truman's biggest rival in the south prevented Dewey from reaching out to voters of those states. Taft's legacy could not be represented against Franklin Roosevelt who had bipartisan support. — Preceding unsigned comment added by 2A02:587:3A0F:5F00:E067:2638:DFC1:10B2 (talk) 21:34, 16 December 2019 (UTC)

Since you're not responing, my arguement is that Dewey should reach out to southern voters and Thurmond prevented him from doing so, leading to Truman winning in contrast to the polls that were correct to their arguement that Truman lacked the momentum that he needed to win but Thurmond overshadowed Dewey despite his radical views that were unappealing to moderate voters that determined the election. Same with Taft's endorsement from the Republican party undermining the campaign of Theodore Roosevelt despite the latter being regarded as one of the best US Presidents ever unlike the former. Romney should reach out to Mike Pence's religious right in 2012 and that's the reason he didn't win similarly to Trump.

https://www.youtube.com/watch?v=e1o5DQexqzU

https://www.austincc.edu/lpatrick/his1302PCM/WhenAllTheExperts2.html — Preceding unsigned comment added by 2A02:587:3A0F:5F00:E067:2638:DFC1:10B2 (talk) 22:36, 16 December 2019 (UTC)

I need a source that says that Thurmond took votes away from Dewey. That's what a spoiler candidate is, and the 1948 election is the only event we should be discussing, not Trump, not Pence, they don't factor into the equation in any meaningful way. The only thing that is important is once again, did Thurmond take votes away from Dewey and ruin his chances of winning... I cannot find anything that says this. Current politics, Taft isn't at all important here Tomasz Magierowski (talk) 13:38, 17 December 2019 (UTC)

LIIA equivalent to IWA

@Wotwotwoot The LIIA == IWA equivalence holds from the standard social choice ⇒ social ordering construction (which I believe I noted, although I might not have made it explicit enough).

The second-place finisher is defined as the winner if the first-place finisher is removed; third-place is defined by results if first+second are removed; etc. This construction implies the first part of LIIA (removing the first k places does not affect finishing order of the remaining candidates) by definition, so we only need the second part: removing the last-k candidates (according to this ordering) does not affect the first-place candidate. Closed Limelike Curves (talk) 18:00, 6 April 2024 (UTC)

That's a good point. I think most readers would intuitively think of an order constructed by the method itself, like Plurality's three-candidate ordering being in the order of "Most first preferences, second most, fewest", not "Most first preferences, pairwise winner of the two others, pairwise loser of the two others", and get the wrong impression from the section stating that LIIA is equivalent to IWA. I'll just note it for the social choice construction at the end of IWA. Wotwotwoot (talk) 18:31, 9 April 2024 (UTC)

I think you're right that's what most people would think; at the same time, "remove and repeat" is probably the most mathematically natural/"correct" way to define the ordering "constructed by the method itself". It's better as a measure of candidate strength (was Le Pen really the 2nd-strongest candidate in 2002?). It's applicable to all systems (What's the "placement order" for River?) and gives a single coherent definition that works for every system, rather than having a different definition for each single-winner system. Closed Limelike Curves (talk) 00:45, 11 April 2024 (UTC)

I think this is a very subtle, but important, point: "worst candidate" needs to be defined consistently across systems for IWA to make sense. Otherwise, you can "hack" IWA (make it trivial) by defining the worst-place candidate according to any set of ballots as the one that, when deleted, doesn't affect the result. (Even if that candidate was actually the runner-up.) Defining "worst" like this lets you claim any system independent of at least one candidate satisfies IWA.

LIIA works because it asks "What's the worst alternative, according to the system itself?" Elimination order ranks candidates from worst to best according to the base method, not according to the new method. The worst candidate, according to a sequential loser method, is the one who could only win if every candidate ahead of them dropped out. Closed Limelike Curves (talk) 04:22, 11 April 2024 (UTC)

@Wotwotwoot Is there some other objective way to consistently define last-place alternative for all systems, besides the last-candidate-to-win construction?

If not, I suppose you could define a criterion like "independence of some alternative", which requires that for any possible ballot profile, at least one candidate other than the winner is not a spoiler. (IRV would satisfy that, since the min-first-place-votes candidate can't be a spoiler; FPTP would fail, since the Condorcet loser can win.) –Maximum Limelihood Estimator 18:15, 17 April 2024 (UTC)

Most systems are already social welfare functions (social ordering functions) and would be familiar to readers as such. For instance, Plurality generates an order of finish from the winner (with the most first preferences) to the loser (with the least). And Arrow's theorem, to pick a well-known result, explicitly deals with methods that return a social ranking.

Treating every method as a social choice function and then leveraging that to create a social welfare function would be confusing, because the social welfare function you end up with differs from the common definition of the method as an SWF.

I am not aware of any analogous election criterion mentioned in literature and directly relating to social choice functions. But I'm not aware of any reference to "independence of worst alternatives" either, so perhaps the best way to deal with the confusion is to delete the IWA section and just refer directly to LIIA. Wotwotwoot (talk) 17:06, 18 April 2024 (UTC)

Most systems are already social welfare functions (social ordering functions) and would be familiar to readers as such. For instance, Plurality generates an order of finish from the winner (with the most first preferences) to the loser (with the least). And Arrow's theorem, to pick a well-known result, explicitly deals with methods that return a social ranking.

I actually had Arrow's theorem in mind when explaining the social ordering construction. The reason I added it is because of a misunderstanding on an old version of the Arrow theorem page, which tried to claim Arrow's theorem wasn't important (because it only dealt with rankings instead of choosing a winner):

In social decision making, to rank all alternatives is not usually a goal. It often suffices to find some alternative. The approach focusing on choosing an alternative investigates either social choice functions (functions that map each preference profile into an alternative) or social choice rules (functions that map each preference profile into a subset of alternatives).

The point of this SRF construction is it's much more relevant to a practical electoral context. Under this construction, the SRF ranks candidates from second-strongest (heir apparent) to weakest (could only win if every other candidate was hit by a bus).

If we use the obvious SWF as the SRF, Arrow's theorem becomes less obviously relevant to an electoral context. After all, what if the change in irrelevant preferences only affected which candidate came in 2nd or 3rd place? Then there'd be no practical importance to IIA if we were holding an election.

The ranking construction makes IIA directly relevant to who wins an election, and questions like "what happens if a candidate drops out"—the common interpretation of Arrow's theorem as describing what can happen when a candidate is added or removed depends on this construction.

The reason for the description in terms of "weakest alternatives" is that requiring the order-of-finish to stay the same if we remove the first-place winner feels quite arbitrary. Explaining the weakest-alternative definition sidesteps all that. –Maximum Limelihood Estimator 03:54, 19 April 2024 (UTC)

I would just say something along the lines of "voters may object that the SWF's change may not involve the winner and thus isn't important. However, a standard construction from social choice functions shows that it also affects winners, hence Arrow is robust in the sense that it can affect the relative ranking of anybody". Or find a source that explains why Arrow is important (clearly there must be one, since it is so widely considered to be important). This would then avoid the confusion of having to deal with SWF/SRFs that look the same but aren't, and would avoid IRV proponents saying "but obviously, if you remove the IRV loser then the order doesn't change, clearly this definition is useless". This would limit the scope where the standard construction is needed so it doesn't cause confusion outside of that scope. Wotwotwoot 13:42, 19 April 2024 (UTC)

@Wotwotwoot what was wrong with the previous edit—I thought you'd suggested removing the information on Independence of Worst Alternatives?

The previous edit tried to make it much more explicit that LIIA was defined according to the candidate-strength ranking. Are there any suggestions you have on improving it?

I'm trying to explain the motivation behind LIIA as intuitively as possible. It doesn't really make sense to me why I'd care if removing the top candidate caused someone other than the second-place finisher to win. In many scenarios it's outright desirable: removing Bill Clinton from the election should cause the more-moderate Ross Perot, not Bob Dole, to win.

OTOH, preventing very weak candidates from spoiling the election (i.e. candidates without any hope of winning) seems very intuitive. –Maximum Limelihood Estimator 01:19, 22 April 2024 (UTC)