Contingent vote
The contingent vote is an electoral system used to elect a single representative in which a candidate requires a majority of votes to win. It is a form of preferential voting. The voter ranks the candidates in order of preference, and when the votes are counted, the first preference votes only are counted. If no candidate has a majority (more than half) of the votes cast, then all but the two leading candidates are eliminated and the votes received by the eliminated candidates are distributed among the two remaining candidates according to voters' preferences. This ensures that one candidate achieves a majority and is declared elected.
Not to be confused with contingent election.
The contingent vote can be considered a compressed or "instant" form of the two-round system (runoff system), in which both "rounds" occur without the need for voters to go to the polls twice. For this reason, the term instant-runoff voting has also been used for this method, though this conflicts with the more common meaning.
It also has similarities to other ranked-choice systems. Unlike the contingent vote, systems like instant-runoff voting (IRV), Coombs' method, and Baldwin's method allow for many rounds of counting, eliminating only one weakest candidate each round. IRV allows a candidate other than the top two in the first count to win.
Usage[edit]
A variant of the contingent vote has been used to elect the president of Sri Lanka since 1978.[1]
The supplementary vote was used to pick directly elected mayors and police and crime commissioners in England prior to 2022.[1]
In the past, the ordinary form of the contingent vote was used to elect the Legislative Assembly of Queensland from 1892 to 1942. To date, this has been the longest continuous use of the system anywhere in the world.[1]
Contingent voting was used for Democratic party primaries in the US state of Alabama from 1915 to 1931.[1]
Impact on factions and candidates[edit]
Like instant-runoff voting and the two-round system, the goal of the contingent vote is to enable a majority of voters to confirm the winner of an election. This majority rule requirement encourages candidates to seek support beyond their core base of supporters in order to secure the lower preferences of the supporters of other candidates. This is said to create a more conciliatory campaigning style among candidates with similar policy platforms. However this effect will be diminished by the fact that lower preferences are less important under the contingent vote than under IRV; under the contingent vote it is especially important for candidates to receive many first preferences so that they are not eliminated straight away.
Compared to plurality voting, the contingent vote does aid the chances of 'third party' candidates to some extent, as voters do not need to be afraid a vote for a minor third party will spoil the election for a stronger party candidate, as long as their second preference candidate can make the top-two requirement.
However, when there are three or more similarly strong candidates, the spoiler effect still exists, just as it does in two-round runoff or IRV: voting honestly for a favorite candidate can cause a second favorite to be eliminated, which then causes a less-preferred candidate to win in the runoff. Likewise, contingent vote suffers from the center-squeeze effect, which can amplify polarization.
Like any system that elects a single representative, contingent vote is not a form of proportional representation. For that reason, if it were used to elect individual members of a council or legislature, it could be expected to produce the kind of one-party-dominant results that are produced by other single-seat systems like first-past-the-post (FPTP) (plurality). However, election of representatives by only a minority of a district's voters is less likely under contingent vote than under FPTP.
Similar systems[edit]
Two-round system[edit]
Under the two-round system (also known as runoff voting and the second ballot) voters vote for only a single candidate, rather than ranking candidates in order of preference. As under the contingent vote, if no candidate has an absolute majority in the first round, all but the top two are eliminated and there is a second round. However, in the two round system, voters are asked to return and vote a second time. Because of the similarities between them, the contingent vote and the two-round system can usually be expected to elect the same winner. However, in the two-round system, the voter is permitted to change one's mind from one round to another, even if their favourite candidate in the first round has not been eliminated. It also guarantees that every voter has a chance to express a preference between the top two, unlike the limited forms of contingent vote. Voter turnout may also be higher in the second vote.
Nonpartisan blanket primary[edit]
The nonpartisan blanket primary is a variation of the two-round system except the first round does not pick a winner, but instead picks the two highest candidates who will compete in the general election. Because the first round does not pick a winner, there will tend to be higher voter turnout in the second election.
The contingent vote will generally pick the same winner as a blanket primary, except fewer voters in the primary round may lead to a different top-two candidates than if the whole electorate voted in both rounds.