“…The ideological differences between political parties-what is commonly understood as party polarization (Dalton, 2008;Sartori, 1966)-clarify the supply side of elections and signal to citizens that their vote matters (Downs, 1957;Ezrow and Xezonakis, 2011;Hobolt and Hoerner, 2020). Party polarization has a formative and galvanizing effect on voters, increasing the likelihood that they develop coherent ideological attitudes and partisan attachments (Adams, Ezrow and Leiter, 2012;Dassonneville, Fournier and Somer-Topcu, 2022;Levendusky, 2010;Lupu, 2015). However, too much polarization can deepen political division and impede democratic compromise and stability (e.g., Bischof and Wagner, 2019;Gidron, Adams and Horne, 2020;Hobolt, Leeper and Tilley, 2021;Iyengar and Westwood, 2015;McCoy, Rahman and Somer, 2018;Wagner, 2021).…”