Center squeeze

Distribution of winners on a simulated political compass, showing how center-squeeze extends to more complex or multi-dimensional models. The number of winners is displayed as a heatmap. The bias of FPTP, runoffs or primaries, and RCV (center-left column) is clearly visible.

Center squeeze is a kind of independence of irrelevant alternatives violation seen in a number of election rules, such as two-round and instant runoff, for example. In a center squeeze, the Condorcet winner is eliminated before they have the chance to face any of the other candidates in a one-on-one race (which by definition, they would win). The term can also refer[according to whom?] to tendency of such rules to encourage polarization among elected officials.

In a center squeeze, candidates focused on appealing to a base of core supporters can squeeze the Condorcet winner out of the race by splitting the first-round vote with them, allowing a more-extreme alternative to win. This effect was first predicted by social choice theorists in the 1940s and 50s, 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)[1] as well as the 2007 French presidential election, where moderate liberal François Bayrou was eliminated by left-wing populist candidate Ségolène Royal, allowing Nicolas Sarkozy to win the second round.[2][3]

  1. ^ Graham-Squire, Adam; McCune, David (2022-09-11). "A Mathematical Analysis of the 2022 Alaska Special Election for US House". p. 2. arXiv:2209.04764v3 [econ.GN]. Since Begich wins both ... he is the Condorcet winner of the election ... AK election also contains a Condorcet loser: Sarah Palin. ... she is also a spoiler candidate
  2. ^ Balinski, Michel; Laraki, Rida (2011), Dolez, Bernard; Grofman, Bernard; Laurent, Annie (eds.), "Election by Majority Judgment: Experimental Evidence", In Situ and Laboratory Experiments on Electoral Law Reform: French Presidential Elections, New York, NY: Springer, pp. 13–54, doi:10.1007/978-1-4419-7539-3_2, ISBN 978-1-4419-7539-3, retrieved 2024-10-31
  3. ^ Balinski, Michel; Laraki, Rida (2020-03-01). "Majority judgment vs. majority rule". Social Choice and Welfare. 54 (2): 429–461. doi:10.1007/s00355-019-01200-x. ISSN 1432-217X.