Condorcet methods Positional voting Cardinal voting Quota-remainder methods Approval-based committees Fractional social choice Semi-proportional representation By ballot type Pathological response Strategic voting Paradoxes of majority rule Positive results Center squeeze is a kind of spoiler effect seen in a number of election rules, among them two-round and instant runoff.

In a center squeeze, the Condorcet winner is eliminated or otherwise rendered irrelevant before they have the chance to face any of the other candidates in a one-on-one race (which by definition, they would win).

[1][5] This effect was first predicted by social choice theorists in the 1940s and 50s,[citation needed] and has since been documented in various countries using plurality-style electoral systems.

Famous examples of center squeezes include the 2022 Alaska special election (where Nick Begich III was eliminated in the first round by Sarah Palin)[6] as well as the 2007 French presidential election, where moderate liberal François Bayrou was eliminated by left-wing candidate Ségolène Royal, allowing Nicolas Sarkozy to win the second round.

[7][8] Center squeezes are a kind of independence of irrelevant alternatives violation in which the Condorcet winner is eliminated before the final round of an election.

[9][10] Candidates focused on appealing to a small base of core supporters can squeeze Condorcet winners out of the race, by splitting the first-round vote needed to survive earlier rounds.

[13] A center squeeze can occur in any situation where voters prefer candidates who hold views similar to their own.

[11] In these methods, candidates must focus on appealing to their core supporters to ensure they can make it past the first round, where only first-preferences count.

As a result, while score voting does not always elect the candidate closest to the median voter, it often behaves like methods that do.

[20][21][22][23] The opposite situation—a bias in favor of bland, inoffensive, or unknown candidates—is not common in any widely-used voting rules.

[6][30] The ranked-choice runoff election involved one Democrat (Mary Peltola) and two Republicans (Sarah Palin and Nick Begich III).

[31][6] The election was also notable as a no-show paradox, where a candidate is eliminated as a result of votes cast in support of their candidacy.

[32][6] However, social choice theorists were careful to note the results likely would have been the same under Alaska's previous primary system as well.

This led several to recommend replacing the system with any one of several alternatives without these behaviors, such as STAR, approval, or Condorcet voting.

[36] In the 2009 election, incumbent Burlington mayor Bob Kiss won reelection as a member of the Vermont Progressive Party,[37] defeating Kurt Wright in the final round with 48% of the vote.

[45][47] The controversy culminated in a successful 2010 initiative that repealed RCV by a vote of 52% to 48%,[48][49] a 16-point shift from the 64% who had supported the 2005 ratification.

[50] Another possible example is the 2016 United States presidential election, where polls found several alternatives including Bernie Sanders and Gary Johnson defeating both Donald Trump and Hillary Clinton under a majority- or rated-voting rules but being squeezed out by both RCV and the primary election rules.

[18][51] Election law scholar Ned Foley criticized the two-round system variant used in the United States, which has been described as a first round of primaries before a de-facto runoff,[52][53] for creating a center squeeze in the 2024 presidential election and thus contributing to political polarization.