Editing Two-round system (section)

== Variants ==
{{More sources needed|section|date=February 2025}}
=== Two-party runoff vote ===
A two-party vote is used for elections to the [[National Assembly (Bhutan)|Bhutanese National Assembly]], where the first round selects two parties that are allowed to compete in the second round. Then, a second round is held using [[single-member district]]s with [[first-past-the-post]].<ref>[http://archive.ipu.org/parline-e/reports/2035_B.htm Bhutanese National Assembly electoral system] {{Webarchive|url=https://web.archive.org/web/20181017010327/http://archive.ipu.org/parline-e/reports/2035_B.htm|date=2018-10-17}} IPU</ref>

=== Top-two primaries ===

In the United States, a two-round system called the [[jungle primary]] and used in [[Elections in Louisiana|Louisiana]] in place of traditional primary elections to choose each party's candidate. In this state, the first round is held on [[Election Day (United States)|Election Day]] with runoffs occurring soon after.

[[Elections in Washington|Washington]] adopted a two-round system [[Initiative 872|in a 2008 referendum]], called the [[nonpartisan blanket primary]] or top-two primary. [[Elections in California|California]] [[California Proposition 14 (2010)|approved the system in 2010]], which was first used for the [[2011 California's 36th congressional district special election|36th congressional district special election]] in February 2011. The first election (the primary) is held ''before'' the general election in November and the top two candidates enter the general election. The general election is always held, even if a candidate gets over 50%.

[[Elections in Georgia (U.S. state)|Georgia]] can have a second round after Election Day if the winner of the first round does not get more than 50%.<ref>{{cite web|url=https://advance.lexis.com/documentpage/?pdmfid=1000516&crid=d8d9613a-497b-44ee-b297-673a3dcaf365&config=00JAA1MDBlYzczZi1lYjFlLTQxMTgtYWE3OS02YTgyOGM2NWJlMDYKAFBvZENhdGFsb2feed0oM9qoQOMCSJFX5qkd&pddocfullpath=%2Fshared%2Fdocument%2Fstatutes-legislation%2Furn%3AcontentItem%3A6348-FW71-DYB7-W31K-00008-00&pdcontentcomponentid=234186&pdteaserkey=sr0&pditab=allpods&ecomp=6s65kkk&earg=sr0&prid=5a7f3049-9a44-4617-955f-31c9d31504d6|title=21-2-501. Number of votes required for election; runoff.}}</ref> However normal partisan primaries are used so it is rare to have more than 2 competitive candidates in the first round.

=== Exhaustive ballot ===
{{main|Exhaustive ballot}}

The exhaustive ballot (EB) is similar to the two-round system, but involves more rounds of voting rather than just two. If no candidate receives an absolute majority in the first round, the candidate with the fewest votes is eliminated. This continues until one candidate has an absolute majority. Because voters may have to cast votes several times, EB is not used in large-scale public elections. Instead it is used in smaller contests such as the election of the presiding officer of an assembly; one long-standing example of its use is in the [[United Kingdom]], where local associations (LCAs) of the [[Conservative Party (UK)|Conservative Party]] use EB to elect their prospective parliamentary candidates (PPCs). Exhaustive ballot is also used by FIFA and the International Olympic Committee to select hosts.

=== Contingent vote ===
{{main|Contingent vote}}

The ''contingent'' or ''supplementary'' vote is a variant of instant-runoff voting that has been used in [[Queensland]] and was previously used in the [[United Kingdom]] to elect some mayors; it was ultimately abandoned as a result of its complex [[election administration]]{{According_to_whom|date=July 2024}}. Under the contingent vote, voters rank the top-two candidates. However it involves only two rounds of counting and uses the same rule for eliminating candidates as the two-round system. After the first round all but the two candidates with most votes are eliminated. Therefore, one candidate always achieves an absolute majority in the second round. Because of these similarities, the contingent vote tends to elect the same winner as the two-round system and instant-runoff voting.

=== Instant-runoff voting ===
{{main|Instant-runoff voting}}

[[Instant-runoff voting]] (IRV), like the exhaustive ballot, involves multiple reiterative counts in which the candidate with fewest votes is eliminated each time. Whilst the exhaustive ballot and the two-round system both involve voters casting a separate vote in each round, under instant-runoff, voters vote only once. This is possible because, rather than voting for only a single candidate, the voter ranks all of the candidates in order of preference. These preferences are then used to transfer the votes of those whose first preference has been eliminated during the course of the count. Because the two-round system and the exhaustive ballot involve separate rounds of voting, voters can use the results of one round to decide how they will vote in the next, whereas this is not possible under IRV. Because it is necessary to vote only once, IRV is used for elections in many places. For such as Australian general and state elections (called ''preferential voting''). In the United States, it is known as [[Ranked-choice voting in the United States|ranked-choice voting]] and is used in a growing number of states and localities.

In [[Republic of Ireland|Ireland]] it is known as the [[single transferable vote]] (STV) and is used for [[Irish presidential election|presidential elections]] and parliamentary elections. However, STV as applied in multi-member districts is a proportional voting system, not a majoritarian one; and candidates need only achieve a quota (or the highest remaining fraction of a quota), to be elected. STV is used in Northern Ireland, Malta, the Australian senate and various other jurisdictions in Australia.<ref>{{cite web |title=Proportional Representation Voting Systems of Australia's Parliaments |url=https://www.ecanz.gov.au/electoral-systems/proportional |url-status=live |archive-url=https://web.archive.org/web/20230302093736/https://www.ecanz.gov.au/electoral-systems/proportional |archive-date=2023-03-02 |access-date=2023-04-09 |website=ECANZ}}</ref> It is often used for municipal elections in lieu of more party-based forms of proportional representation.