Top-four primary

A top-four primary or top-four ranked-choice voting is an election method using a nonpartisan blanket primary where up to four candidates, those with the most votes, advance from a first round of voting, regardless of the political party. The "round two" (general) election, held some weeks later, uses instant-runoff voting ("IRV", also known as "ranked-choice voting", "RCV") to confirm a majority winner among the top set of candidates.
Its first use was in 2022 Alaska's at-large congressional district special election. It can be seen as a replacement to the "blanket primary" which advances only the "top-two" candidates. It was first advocated by FairVote in 2012 with a statutory model proposed in 2015.
A "top-four primary" can be seen as a variation of a two-round system where the second round (general election) is always held, even if a candidate gains a majority in the first (primary) round. A candidate receiving 20% of the primary vote is logically guaranteed to pass a top-four primary.
One variation, called Final Five Voting (FFV), allows five candidates to pass the open primary.
Usage.
Top-four.
Alaska.
The 2020 Alaska Measure 2 initiative in Alaska for "top-four primary" narrowly passed with 50.55% of the vote. It will be used for all state and federal elections except for the president. The Alaskan Independence Party sued, declaring Ballot Measure 2 as unconstitutional. On January 19, 2022, the Alaska Supreme Court ruled that the measure was constitutional.
The blanket primary is held using first past the post, with voters allowed one vote, and the four candidates with the most votes advancing to the general. The general election ballot allows candidates to be ranked, using Instant-runoff voting elimination to identify a majority winner. The first top-four primary election occurred on August 16, 2022.
For Alaska's 2022 at-large congressional district special election, 48 candidates registered, while only 9 candidates were invited to a first panel discussion: 5 Republicans, 2 Democrats and 2 independents based on various criteria. Despite 48 candidates, the Special election June primary resulted in the top-4 candidates gaining 68.8% of the vote: Sarah Palin 27.01%, Nick Begich, III 19.12%, Al Gross 12.63%, Mary Peltola 10.08%, with the 5th candidate Tara Sweeney at 5.92%. Al Gross withdrew after the primary, and suggested 5th place Sweeney be included in the final ballot, but this was not allowed. In the general election, Republican votes were split between Palin and Peltola, causing Begich to be eliminated first (despite being preferred over both other candidates). Votes were then transferred to both Palin and Peltola, resulting in Peltola winning.
Missouri.
The "Better Elections" campaign of Missouri collected 300,000 signature for a Top-Four Ranked-Choice Voting for local, state, and Federal Officials, needing 160,199 valid signatures. The initiative would have been voted on in November 2022. However, the signatures needed to be distributed among six congressional districts to qualify, and the campaign did not collect enough in Missouri's 1st District, so the initiative was rejected. The ballot initiative will be attempted again.
Top-five.
Petitions sponsored by Katherine M. Gehl and "Institute for Political Innovation".
Nevada.
"Nevada Voters First" has a petition for a Top-Five Ranked-Choice Voting Initiative, if enough signatures will appear on the ballot on November 8, 2022. At least 135,561 valid signatures are required by June 21, 2022 for the initiative to make the ballot, with, the group backing the voting overhaul,announcing it has gathered more than 266,000 signatures.
The initiative would amend the Nevada Constitution to establish "open top-five primaries" and instant-runoff voting for general elections. It would allow the 35% of voters who are not registered to a party to influence the candidates who advance to the general election. The change would apply to congressional, gubernatorial, state executive offices, and state legislative elections. Supportive legislation would be required for adopted by July 1, 2025.
Vote splitting.
With a pick-one, top-four primary, advancing "top-four" candidates maintains a threat of vote splitting, same as a "pick-one" nonpartisan blanket primary top-two primary, just a little more generous with 4 candidates remaining. There may be multiple candidates eliminated below fourth place, while some could have advanced if fewer candidates had run and split their vote.
For illustration, a party with 48% could theoretically win all top-four if their four candidates each earned 12%, while a stronger 52% majority party might equally split their votes at 10.4% each and lose all five candidates. Vote-splitting will be experienced as threatening to parties who may lose all their candidates, compared to a closed primary where one candidate from each party always advances.
Likewise, the use of sequential-elimination ranked IRV in the primary also suffers from vote-splitting. Candidates are eliminated based only on first-choice votes, which become split between similar candidates vying for them. The transfer of votes between candidates mitigates this effect somewhat (when two candidates have identical appeal to voters and their votes wholly transfer to each other) but does not eliminate it in the general case, as advocates claim. To avoid vote-splitting in the RCV general election, parties must still try to discourage too many candidates running under their label, and party voters need to be informed which candidates are most likely to advance to avoid wasting their vote.
An argument in favor of a "pick-one top-four primary" is that people's first rank choices are most important and the eventual winner of the election will most likely be among the top-four first-rank choices. A "pick-one top-four primary" can be considered a single non-transferable vote (SNTV) system.
An argument in favor of using IRV sequential-elimination in the primary is that more voters help pick the top-four, and marginally more will be happy with supporting at least one in the general election.
Variations.
The uniting feature of all variations is to reduce the field of candidates in a primary round, and confirming a majority winner in the general election. Ranked ballots enables a majority winner among more than two candidates.
Summary.
All of these variations, including a traditional nonpartisan blanket primary, allow a majority to confirm the winner.