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|Part of the Politics series|
|Voting patterns and effects|
Vote splitting is an electoral effect in which the distribution of votes among multiple similar candidates reduces the chance of winning for any of the similar candidates, and increases the chance of winning for a dissimilar candidate.
Vote splitting most easily occurs in plurality voting (also called first-past-the-post) in which each voter indicates a single choice and the candidate with the most votes wins, even if the winner does not have majority support.For example, if candidate A1 receives 30% of the votes, similar candidate A2 receives another 30% of the votes, and dissimilar candidate B receives the remaining 40% of the votes, plurality voting declares candidate B as the winner, even though 60% of the voters prefer either candidate A1 or A2.
Under such systems vote pairing (also called vote swapping, co-voting or peer to peer voting) can mitigate the effect, but it requires two voters in different districts to agree, and identifying probabilities of candidates winning in those districts. A vote swap effectively preserves the total support for each party but moved it to where it is most effective. It is legal and practiced in US,Canadian & especially UK elections.
Cardinal voting methods are immune to vote splitting, since each candidate is rated independently of each other.Pairwise-counting Condorcet methods minimize vote splitting effects. Plurality-runoff voting methods (like Exhaustive ballot, Two-round system/Top-two primary, Instant-runoff voting, Supplementary vote, and Contingent vote) still suffer from vote-splitting in each round, but can somewhat reduce its effects compared to single-round plurality voting.
A well-known effect of vote splitting is the spoiler effect, in which a popular candidate loses an election by a small margin because a less-popular similar candidate attracts votes away from the popular candidate, allowing a dissimilar candidate to win. As a result, the notion of vote splitting is controversial because it can discourage third party candidates.
Strategic nomination takes advantage of vote splitting to defeat a popular candidate by supporting another similar candidate.
Vote splitting is one possible cause for an electoral system failing the independence of clones or independence of irrelevant alternatives fairness criteria.
Different electoral systems have different levels of vulnerability to vote splitting.
Vote splitting most easily occurs in plurality voting because the ballots gather only the least bad preference of the voter.In the United States vote splitting commonly occurs in primary elections. The purpose of primary elections is to eliminate vote splitting among candidates in the same party before the general election. If primary elections or party nominations are not used to identify a single candidate from each party, the party that has more candidates is more likely to lose because of vote splitting among the candidates from the same party. Primary elections occur only within each party and so vote splitting can still occur between parties in the secondary election. In open primaries, vote splitting occurs between all candidates.
In addition to applying to single-winner voting systems (such as used in the United Kingdom, the United States and Canada), a split vote can occur in proportional representation methods that use election thresholds, such as in Germany, New Zealand and Turkey. In those cases, "fringe" parties that do not meet the threshold can take away votes from larger[ clarification needed ] parties with similar ideologies.
When ranked ballots are used, voters can vote for a minor party candidate as their first choice and indicate their order of preference for the remaining candidates, without regard to whether a candidate is in a major political party. For example, voters who support a very conservative candidate can select a somewhat-conservative candidate as their second choice, thus minimizing the chance that their vote will result in the election of a non liberal candidate.
Runoff voting is less vulnerable to vote splitting than is plurality voting, but vote splitting can occur in any round of runoff voting.
Vote splitting rarely occurs when the chosen electoral system uses ranked ballots and a pairwise-counting method, such as a Condorcet method.Pairwise counting methods do not involve distributing each voter's vote between the candidates. Instead, pairwise counting methods separately consider each possible pair of candidates for all possible pairs. For each pair of candidates, there is a count for how many voters prefer the first candidate (in the pair) to the second candidate and how many voters have the opposite preference. The resulting table of pairwise counts eliminates the step-by-step distribution of votes, which facilitates vote splitting in other voting methods.
Voting methods that are vulnerable to strategic nomination, especially those that fail independence of clones, are vulnerable to vote splitting. Vote splitting also can occur in situations that do not involve strategic nomination, such as talent contests (such as American Idol ) in which earlier rounds of voting determine the current contestants.
Cardinal voting methods require an independent score to be given to candidates, as opposed to a ranking. The three primary methods are approval voting, with a range between 0-1, score voting with an arbitrary range, and STAR voting.
All cardinal voting methods are immune to vote splitting, as each candidate is evaluated independently of each other candidate.
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When three-cornered contests do occur the Labor Party would usually direct preferences to the Liberals ahead of the Nationals as they considered the Liberal Party to be less conservative than the Nationals. The 1996 Southern Highlands state by-election in New South Wales is an example of this when the Nationals candidate Katrina Hodgkinson won the primary vote but was defeated after preferences to Liberal candidate Peta Seaton when Seaton received Labor Party preferences.
The spoiler effect is the effect of vote splitting between candidates or ballot questions 's presence in the election draws votes from a major candidate with similar politics, thereby causing a strong opponent of both or several to win. The minor candidate causing this effect is referred to as a spoiler. However, short of any electoral fraud, this presents no grounds for a legal challenge.who often have similar ideologies. One spoiler candidate
The spoiler effect is a problem in plurality voting systems because they enable a candidate to win with less than half of the vote.
The problem also exists in two round system and instant-runoff voting Mathematical definitions).though it is reduced, because weaker spoilers are eliminated, however a candidate that can win head-to-head against all rivals (Condorcet winner) can still lose from third place in a 3 way vote split. Other preferential voting or ranked ballot voting systems also suffer from variations of the spoiler effect, as they fail the independence of irrelevant alternatives (IIA) criterion (see §
The problem does not exist in cardinal voting methods like approval voting, score voting, or majority judgment, since the rating of each candidate is independent of the ratings of other candidates.
The spoiler candidate takes votes away from a more viablecandidate or candidates, a common effect called vote splitting. If one opposing candidate is ideologically or politically similar and therefore receives far fewer votes than other opposing candidates to the spoiler candidate, vote splitting has a spoiler effect.
In some cases, even though spoiler candidates cannot win themselves, their influence upon the voters may enable the candidate to determine deliberately the more viable candidate who wins the election, a situation known as a kingmaker scenario. With a first-past-the-post voting system, that is particularly feasible when spoiler candidates recommend tactical voting or run on a false manifesto to bolster the prospects for their secretly-preferred candidate to win.
In a preferential voting system, voters can feel more inclined to vote for a minor party or independent as their first choice and can record a preference between the remaining candidates, whether they are in a major or established party or not. For example, voters for a minor left-wing candidate might select a major left-wing candidate as their second choice, thus minimizing the probability that their vote will result in the election of a right-wing candidate, or voters for an independent candidate perceived as libertarian, or simply as the voter prefers that ideology might select a particular libertarian candidate as their second choice, thus minimizing the probability of an authoritarian candidate being elected. Approval voting and proportional representation systems can also reduce the spoiler effect.
One of the main functions of political parties is to mitigate the effect of spoiler-prone voting methods by winnowing on a local level the contenders before the election. Each party nominates at most one candidate per office since each party expects to lose if they nominate more than one.In some cases, a party can expect to "lose" by "suffering a rival elected opponent" if they nominate more than zero, where two opponents exist and one is considered a candidate they can "work with" — a party may prefer the candidate who would win if the party nominates zero.
Thus, empirical observations of the frequency of spoiled elections do not provide a good measure of how prone to spoiling a particular voting method is, since the observations omit the relevant information about potential candidates who did not run because of not wanting to spoil the election.
Possible mathematical definitions for the spoiler effect include failure of the independence of irrelevant alternatives (IIA) axiom, and vote splitting.
Arrow's impossibility theorem states that rank-voting systems are unable to satisfy the independence of irrelevant alternatives criterion without exhibiting other undesirable properties as a consequence. However, different voting systems are affected to a greater or lesser extent by IIA failure. For example, instant runoff voting is considered to have less frequent IIA failure than First Past the Post (also known as Plurality Rule). The independence of Smith-dominated alternatives (ISDA) criterion is much weaker than IIA; unlike IIA, some ranked-ballot voting methods can pass ISDA.
A possible definition of spoiling based on vote splitting is as follows: Let W denote the candidate who wins the election, and let X and S denote two other candidates. If X would have won had S not been one of the nominees, and if (most of) the voters who prefer S over W also prefer X over W (either S>X>W or X>S>W), then S is a spoiler. Here is an example to illustrate: Suppose the voters' orders of preference are as follows:
|33%: S>X>W||15%: X>S>W||17%: X>W>S||35%: W>X>S|
The voters who prefer S over W also prefer X over W. W is the winner under Plurality Rule, Top Two Runoff, and Instant Runoff. If S is deleted from the votes (so that the 33% who ranked S on top now rank X on top) then X would be the winner (by 65% landslide majority). Thus S is a spoiler with these three voting methods.
A 2014 analysis by Philip Bump for the Washington Post found that 1.5% of general election races in the U.S. from 2006 to 2012 were spoiled by third-party candidates.
Historically, the Democratic and Republican parties have benefited from the alleged spoiler effect created by the existing U.S. plurality voting system.This benefit is based in the theory that not voting for other parties and for independents and that third parties and independent candidates themselves declining to run, means to avoid "wasting votes" or splitting the vote causing an election result not wanted.
There are third-party candidates who have been accused of denying victory to a major nominee in U.S. Presidential Elections; a notable case among these is the 1912 election, where Progressive Party candidate Theodore Roosevelt won almost 700,000 votes more than did the Republican incumbent, William Howard Taft,and thus it could be said that Taft was the spoiler for Roosevelt in that election. This argument worried Republicans, who, after Woodrow Wilson won the 1912 election, became concerned that Roosevelt might return to split the Republican vote again.
In 1968, George Wallace ran for president as the American Independent Party's nominee. He received numerous votes from Southern demographics that typically voted for Democratic candidates, thereby undercutting the candidacy of that election's Democratic nominee, Hubert Humphrey.
The 2000 U.S. Presidential election is often cited as an example of the spoiler effect. In that election, Al Gore, the Democratic candidate, received more popular votes than George W. Bush, the Republican candidate, but lost in the electoral college. In the state of Florida, the final certified vote count showed Bush with just 537 more votes than Gore.Because Bush defeated Gore in Florida, he won the state, received more votes in the electoral college, and became president of the United States.
Gore supporters argued that had candidate Ralph Nader, a progressive, not run in the election, the majority of the 97,421 votes he received in Florida would have been cast for Gore. Thus, they contend that Nader's candidacy spoiled the election for Gore by taking away enough votes from Gore in Florida to swing the election to Bush. Their argument is bolstered by a poll of Nader voters, asking them for whom they would have voted had Nader not run, which said 45 percent of Nader voters would have voted for Gore, 27 percent would have voted for Bush, and the rest would not have voted.
Nader himself and many of his supporters argued that most Nader voters would either have chosen another minor party candidate or abstained from voting, had Nader not been on the ballot. All other third party candidates on the ballot in Florida received more than the 537 vote difference between Bush and Gore.Still, some observers began to refer to the spoiler effect as the "Nader effect" after the 2000 election. A 2006 study found that at least 40% of Nader voters in Florida would have voted for Bush if Nader had not run, while the other 60% would have voted for Gore. The study concluded that this 60% "did indeed spoil the 2000 presidential election for Gore but only because of highly idiosyncratic circumstances, namely, Florida’s extreme closeness."
In the German presidential election of 1925, Communist Ernst Thälmann refused to withdraw his candidacy although it was extremely unlikely that he would have won, and the leadership of the Communist International urged him not to run. In the second (and final) round of balloting, Thälmann won 1,931,151 votes (6.4%). Centre Party candidate Wilhelm Marx, backed by pro-republican parties, won 13,751,605 (45.3%). The right-wing candidate Paul von Hindenburg won 14,655,641 votes (48.3%).If most of Thälmann's supporters had voted for Marx, Marx would have won the election. That election had great significance because after 1930, Hindenburg increasingly favoured authoritarian means of government, and in 1933, he appointed Adolf Hitler as chancellor. Hindenburg's death the following year gave Hitler unchecked control of the German government.
In New Zealand, there have been two notable cases of the spoiler effect. In the 1984 general election, the free-market New Zealand Party deliberately ran for office to weaken support former Prime Minister Robert Muldoon, the incumbent. The 1993 general election saw the New Zealand Labour Party's vote split by The Alliance, which has been attributed to the vagaries of the plurality vote. In response to these problems, New Zealand has since adopted mixed-member proportional representation.
Likewise, in France, the 2002 presidential elections have been cited as a case of the spoiler effect: the numerous left-wing candidates, such as Christiane Taubira and Jean-Pierre Chevènement, both from political parties allied to the French Socialist Party, or the three candidates from Trotskyist parties, which altogether totalled around 20%, have been charged with making Lionel Jospin, the Socialist Party candidate, lose the two-round election in the first round to the benefit of Jean-Marie Le Pen, who was separated from Jospin by only 0.68%. Some also cite the case of some districts in which the moderate right and the far right had more than half of the votes together, but the left still won the election; they accuse the left of profiting from the split.
In Hong Kong, vote splitting is very common for the pro-democracy camp, which caused it to suffer greatly in many elections, including the 2016 Hong Kong legislative election and the 2015 Hong Kong local elections. Pro-democracy supporters typically have different ideologies and suffer from factional disputes that are exacerbated after the advent of localist groups. However, many have wider aggregate support fewer seats are earned than the pro-Beijing camp, an example being in Kowloon East in which pro-democracy parties got over 55% of cast ballots but won only 2 seats out of 5.
In Canada, vote splits between the two major left-wing parties assisted the Conservative Party in winning the 2006, 2008, and 2011 federal elections, despite most of the popular vote going to left-wing parties in each race.
Also in Canada, the 2015 provincial election in Alberta saw the left-wing New Democratic Party win 62% of the seats with 40.6% of the province's popular vote after a division within the right-wing Progressive Conservative Party, which left it with only 27.8% of the vote, and its breakaway movement, the Wildrose Party, with 24.2% of the vote. In 2008, the last election in which the Progressive Conservative Party had been unified, it won 52.72% of the popular vote.
In Greece, Antonis Samaras was the Minister for Foreign Affairs for the liberal conservative government of New Democracy under Prime Minister Konstantinos Mitsotakis but ended up leaving and founding the national conservative Political Spring in response to the Macedonia naming dispute, resulting in the 1993 Greek legislative election where PASOK won with its leader Andreas Papandreou making a successful political comeback, which was considered to be responsible for the Greek government debt crisis.
In the run up to 2019 UK General Election, the Brexit Party, led by former UKIP leader Nigel Farage, initially put up candidates in 600 seats after a strong showing for the newly-formed party in the 2019 European Elections, but days later, he reversed his position after Conservative British Prime Minister Boris Johnson stated that he would not consider an electoral pact with the Brexit Party. That was seen as benefiting the Conservative Party and disadvantaging the Labour Party.Farage later encouraged voters not to vote for the Labour Party in areas that traditionally favoured it but voted to leave in the 2016 EU Membership Referendum but instead to vote tactically. After the Conservatives' decisive victory, it was suggested by some media outlets and political analysts that Farage had acted as "kingmaker" and stalking horse and effectively won the election for the Tories, as Farage's decision avoided splitting the vote.
Plurality voting is an electoral system in which each voter is allowed to vote for only one candidate, and the candidate who polls more than any other counterpart is elected. In a system based on single-member districts, it may be called first-past-the-post (FPTP), single-choice voting, simple plurality or relative/simple majority. In a system based on multi-member districts, it may be referred to as winner-takes-all or bloc voting.
The two-round system is a voting method used to elect a single candidate, where voters cast a single vote for their preferred candidate. The election proceeds to a second round only if in the first round no candidate has received a simple majority of votes cast, or at least some other prescribed percentage. In the second round, usually only the two candidates who received the most votes in the first round, or those candidates who received above a prescribed proportion of the votes, would be candidates in the second round. Any remaining candidate is free to withdraw from the second round.
In voting methods, tactical voting occurs in elections with more than two candidates, when a voter supports another candidate more strongly than their sincere preference in order to prevent an undesirable outcome.
The 2000 United States presidential election was the 54th quadrennial presidential election, held on Tuesday, November 7, 2000. Republican candidate George W. Bush, the governor of Texas and eldest son of the 41st president, George H. W. Bush, won the disputed election, defeating Democratic nominee Al Gore, the incumbent vice president. It was the fourth of five American presidential elections, and the first in 112 years, in which the winning candidate lost the popular vote, and is considered one of the closest elections in US history.
The 1996 United States presidential election was the 53rd quadrennial presidential election, held on Tuesday, November 5, 1996. Incumbent Democratic President Bill Clinton defeated former Senate Majority Leader Bob Dole, the Republican nominee, and Ross Perot, the Reform Party nominee.
In political science, Duverger's law holds that single-ballot plurality-rule elections structured within single-member districts tend to favor a two-party system.
[T]he simple-majority single-ballot system favours the two-party system.
The 1992 United States presidential election was the 52nd quadrennial presidential election, held on Tuesday, November 3, 1992. Democratic Governor Bill Clinton of Arkansas defeated incumbent Republican President George H. W. Bush, independent businessman Ross Perot of Texas, and a number of minor candidates. This election marked the end of a period of Republican dominance that began in 1968, Bush was the last U.S. president and the tenth incumbent president in the country's history to lose a bid for a second term, until Donald Trump in 2020.
Primary elections, often abbreviated to primaries, are a process by which voters can indicate their preference for their party's candidate, or a candidate in general, in an upcoming general election, local election, or by-election. Depending on the country and administrative divisions within the country, voters might consist of the general public in what is called an open primary, or solely the members of a political party in what is called a closed primary. In addition to these, there are other variants on primaries that are used by many countries holding elections throughout the world.
In a first-past-the-post electoral system, voters cast their vote for a candidate of their choice, and the candidate who receives the most votes wins. FPTP is a plurality voting method, and is primarily used in systems that use single-member electoral divisions. FPTP is used as the primary form of allocating seats for legislative elections in about a third of the world's countries, mostly in the English-speaking world.
Terminology: In the UK and Australia, pairing is the mechanism by which two members of parliament of opposing parties agree, with the consent of their party whips, to abstain from voting if the other one is unable to vote. Thus they maintain the balance of votes if one or the other is unable to attend. A three-line whip would usually be excepted from this agreement. For MPs who are not paired a bisque, a rota system allowing absence is used. This article is not about this process, but about peer to peer voting in elections among constituents.
Third party is a term used in the United States for American political parties other than the Republican and Democratic parties. Sometimes the phrase "minor party" is used instead of third party.
In United States presidential elections, an unpledged elector is a person nominated to stand as an elector but who has not pledged to support any particular presidential or vice presidential candidate, and is free to vote for any candidate when elected a member of the Electoral College. Presidential elections are indirect, with voters in each state choosing electors on Election Day in November, and these electors choosing the president and vice president of the United States in December. Electors in practice have since the 19th century almost always agreed in advance to vote for a particular candidate — that is, they are said to have been pledged to that candidate. In the 20th century, however, several elections were contested by unpledged electors, who made no pledge to any candidate before the election. These anomalies largely arose from fissures within the Democratic Party over the issues of civil rights and segregation. No serious general election campaign has been mounted to elect unpledged electors in any state since 1964.
Elections in Georgia are held to fill various state and federal seats. Georgia regular elections are held every even year. The positions being decided each year varies, as the terms of office varies. The State Senate, State House and U.S. House will typically be up for election, as all of those positions have two-year terms. Special elections are held to fill vacated offices. Georgia is one of seven states that require a run-off election if no candidate receives a majority of the vote in a primary election. Uniquely, Georgia requires a run-off election for state and congressional offices if no candidate wins a majority of the vote in a general election; only Louisiana has a similar requirement, but it operates under a different election system.
Like virtually all other electoral systems, in the two-round system, there is potential for both tactical voting and strategic nomination. Tactical voting is where voters do not vote in accordance with their true preferences, but instead vote insincerely in an attempt to influence the result. Runoff voting is intended as a method that reduces tactical voting, but two tactics called compromising and pushover are still possible in many circumstances. In particular voters are strongly encouraged to compromise by voting for one of the three leading candidates in the first round of an election.
The 2000 presidential campaign of Ralph Nader, political activist, author, lecturer and attorney, began on February 21, 2000. He cited "a crisis of democracy" as motivation to run. He ran in the 2000 United States presidential election as the nominee of the Green Party. He was also nominated by the Vermont Progressive Party and the United Citizens Party of South Carolina. The campaign marked Nader's second presidential bid as the Green nominee, and his third overall, having run as a write-in campaign in 1992 and a passive campaign on the Green ballot line in 1996.
Instant-runoff voting (IRV), also sometimes referred to as the alternative vote (AV), preferential voting, or, in the United States, ranked-choice voting (RCV), though these names are also used for other systems, is a type of ranked preferential voting counting method used in single-seat elections with more than two candidates.
In the United States, presidential plurality victories are those elections in which the winning candidate received less than 50% of the popular votes cast but the largest share of votes.
The 2000 United States presidential election in New Hampshire took place on Election Day on November 7, 2000 as part of the 2000 United States presidential election. The 2 major candidates were Texas Governor George W. Bush of the Republican Party and sitting Vice President Al Gore of the Democratic Party. When all votes were tallied, Bush was declared the winner with a plurality of the vote over Gore, receiving 48% of the vote to Gore's 47%, while Green Party candidate Ralph Nader received almost 4% of the vote in the state. Bush went on to win the election nationwide. Had incumbent Vice President Gore come out victorious with New Hampshire and its four electoral votes, he would have won the presidency. As of the 2020 presidential election, this is the last time that the Republican nominee carried New Hampshire. It also marked the last time that a Republican won any electoral votes in New England, until Donald Trump won Maine's 2nd congressional district in 2016.
The city of Burlington, Vermont held a mayoral election on March 3, 2009. This was the second mayoral election since the city's 2005 approval of instant-runoff voting (IRV). The incumbent mayor Bob Kiss, who had served since 2006, successfully won reelection on the Vermont Progressive line.
A unified primary is an electoral system for narrowing the field of candidates for a single-winner general election, similar to a nonpartisan blanket primary, but using approval voting for the first round.
plurality-rule voting is seriously vulnerable to vote-splitting ... runoff voting ... as French history shows, it too is highly subject to vote-splitting. ... [Condorcet] majority rule avoids such vote-splitting debacles because it allows voters to rank the candidates and candidates are compared pairwise
IRV is subject to something called the "center squeeze." A popular moderate can receive relatively few first-place votes through no fault of her own but because of vote splitting from candidates to the right and left. ... Approval voting thus appears to solve the problem of vote splitting simply and elegantly. ... Range voting solves the problems of spoilers and vote splitting
You likely have opinions about all those candidates. And yet, you only get a say about one.
a spoiler effect occurs when entry by a third-party candidate causes party A to defeat party B even though Party B would have won in a two-candidate race.
Those votes that are cast for minor party candidates are perceived as taking away pivotal votes from major party candidates. ... This phenomenon is known as the 'spoiler effect'.
Candidates C and D spoiled the election for B ... With them in the running, A won, whereas without them in the running, B would have won. ... Instant runoff voting ... does not do away with the spoiler problem entirely, although it ... makes it less likely
A spoiler effect occurs when a single party or a candidate entering an election changes the outcome to favor a different candidate.
IRV is excellent for preventing classic spoilers-minor candidates who irrationally tip the election from one major candidate to another. It is not so good when the 'spoiler' has a real chance of winning
After a minor party is strong enough to win, on the other hand, a vote for them could have the same spoiler effect that it could have under the current plurality system
IRV means betraying your true favorite third party candidate pays off. Voting third party can mean wasting your vote under IRV, just like under plurality.