First-past-the-post voting
First-past-the-post —also called choose-one, first-preference plurality, or simply plurality—is a single-winner voting rule. Each voter marks one candidate as their favorite, or first-preference, and the candidate with more first-preference votes than any other candidate is elected, even if they do not have more than half of votes.
FPP has been used to elect part of the British House of Commons since the Middle Ages before spreading throughout the British Empire, usually in conjunction with plurality block voting. Throughout the 20th century, the former British colonies of Australia and New Zealand and many other countries that were using FPP abandoned FPP in favor of other electoral systems. FPP is still officially used in the majority of US states for most elections. However, the combination of partisan primaries and a two-party system in these jurisdictions means that most American elections behave effectively like two-round systems, in which the first round chooses two main contenders.
Example
In FPTP, only the first preferences matter. As such, the votes would be counted as 42% for Memphis, 26% for Nashville, 17% for Knoxville, and 15% for Chattanooga. Since Memphis has the most votes, it would win a FPTP election, even though it is far from the center of the state and a larger majority of voters would more strongly prefer Nashville than any other option. Conversely, instant-runoff voting would elect Knoxville, the easternmost city. Such an election result would be an example of center squeeze.By contrast, both Condorcet methods and score voting would return Nashville.
Properties and effects
Two-party rule
Perhaps the most striking effect of FPP is the fact that the number of a party's seats in a legislature has little to do with its vote count in an election, only in how those votes were geographically distributed. Parties with few votes sometimes take more than few seats; often the most-popular party takes 20 percent more seats than its portion of the popular vote. Some criticize FPP for this, arguing that a fundamental requirement of an election system is to accurately represent the views of voters. FPP often creates "false majorities" by over-representing larger parties while under-representing smaller ones.In Canada, majority governments have been formed often but usually they are made up of a party that received less than a majority of votes in the election. A party forming a majority government and also winning a majority of the votes cast has happened only six times since 1900: 1900; 1904; 1917; 1940, 1958 and 1984.
In the United Kingdom, 19 of the 24 general elections since 1922 have produced a single-party majority government. In only two of them, the leading party took a majority of the votes across the UK.
In some cases, this can lead to a party receiving the plurality or even majority of the votes cast overall, yet still failing to gain a plurality of legislative seats. This results in a situation called a majority reversal or electoral inversion or wrong-winner result. Famous examples of the second-place party winning a majority of seats include the elections in Ghana in 2012, New Zealand in 1978 and 1981, and the United Kingdom in 1951.
Famous examples of the second most popular party winning a plurality of seats include the elections in Canada in 2019 and 2021. Even when a party wins more than half the votes in an almost purely two-party-competition, it is possible for the runner-up to win a majority of seats. This happened in Saint Vincent and the Grenadines in 1966, 1998, and 2020 and in Belize in 1993. Even with only two parties and equally-sized constituencies, winning a majority of seats just requires receiving more than half the vote in more than half the districts—even if the other party receives all the votes cast in the other districts—so just over a quarter of the vote is theoretically enough to win a majority in the legislature. With enough candidates splitting the vote in a district, the total number of votes needed to win can be made arbitrarily small.
Under first-past-the-post, a small party may draw votes and seats away from a larger party that it is more similar to, and therefore give an advantage to one it is less similar to. For example, in the 2000 United States presidential election, the left-leaning Ralph Nader drew more votes from the left-leaning Al Gore, resulting in Nader spoiling the election for the Democrats. According to the political pressure group Make Votes Matter, FPTP creates a powerful electoral incentive for large parties to target similar segments of voters with similar policies. The effect of this reduces political diversity in a country because the larger parties are incentivized to coalesce around similar policies. The ACE Electoral Knowledge Network describes India's use of FPTP as a "legacy of British colonialism".
Duverger's law is an idea in political science which says that constituencies that use first-past-the-post methods will lead to two-party systems, given enough time. Economist Jeffrey Sachs explains:
However, most countries with first-past-the-post elections have multiparty legislatures, the United States being the major exception. There is a counter-argument to Duverger's Law, that while on the national level a plurality system may encourage two parties, in the individual constituencies supermajorities may cause the largest party to suffer fracturing.
Strongholds, key constituencies and kingmakers
The distortions in geographical representation provide incentives for parties to "write off regions" where they are weak and not have much chance of being elected. So they ignore the interests of areas in which they are too weak to stand much chance of gaining representation, leading to governments that do not govern in the national interest.Further, during election campaigns the campaigning activity of parties tends to focus on marginal seats held by opponents where there is a prospect of a change in representation. These decisions leave safer areas excluded from participation in an active campaign. Political parties operate by targeting districts, directing their activists and policy proposals toward those areas considered to be marginal, either possible to be lost or won, where each additional vote is potentially more critical and has more value.
The ability of FPTP to manufacture majority governments has been cited by its supporters as an advantage over proportional representation systems. In the latter, smaller parties may act as 'kingmakers' in coalitions using their bargaining power and therefore, arguably, their influence on policy is more than proportional to their parliamentary size. This is largely avoided in FPP systems where majorities are generally achieved, even if the party holding power does not have majority of votes. FPP often produces governments which have legislative voting majorities, thus providing such governments the legislative power necessary to implement their electoral manifesto commitments during their term in office, if they choose to.
This may be beneficial in a country where the party's legislative agenda has broad public support, albeit potentially divided across party lines, or at least benefits society as a whole. However handing a legislative voting majority to a government that lacks popular support can be problematic where said government's policies favor only a fraction of the electorate, particularly if the electorate divides on tribal, religious, or urban–rural lines. There is also the perceived issue of unfair coalitions where a smaller party forms a coalition with other smaller parties and form a government, without a clear mandate as was the case in the 2009 Israeli legislative election where the leading party Kadima, was unable to form a coalition so Likud, a smaller party, formed a government without being the largest party.
The use of proportional representation may enable smaller parties to become decisive in the country's legislature and gain leverage they would not otherwise enjoy, although this can be somewhat mitigated by a large enough electoral threshold. FPP supporters argue that FPP generally reduces this possibility, except where parties have a strong regional basis. A journalist at Haaretz reported that Israel's highly proportional Knesset "affords great power to relatively small parties, forcing the government to give in to political blackmail and to reach compromises"; Tony Blair, defending FPP, argued that other systems give small parties the balance of power, and influence disproportionate to their votes.
The concept of kingmaker small parties is similar to Winston Churchill's criticism of the alternative vote system as "determined by the most worthless votes given for the most worthless candidates." meaning that votes for lesser-supported candidates may change the outcome of the election between the most-popular candidates. In this case however, it is an intended feature of the alternative vote, since those votes would have otherwise been wasted. In some sense the cross-party vote transfers make every vote count, as opposed to FPP, where as many as three-quarters or more of the votes may be wasted in a district. Anyway this effect is only possible when no candidate receives a majority of first preference votes. It is related to kingmaker premise in that the lesser-known candidates may encourage their supporters to rank the other candidates a certain way and thus have undue influence.
Supporters of electoral reform generally see the kingmaker ability as a positive development, and claim that cross party ties produced by some alternatives to FPP encourage less negative campaigning and encourage more positive campaigning, as candidates are pushed to appeal to a wider group of people. Opinions are split on whether the alternative vote achieves this better than other systems.