Concept and measurement
Poole and Rosenthal (1984) used roll-call votes to estimate legislators' ideal points and showed the parties drifting apart. Ideological polarization concerns distance in policy positions, unlike affective polarization, which concerns hostility toward the other party.
Are the masses polarized?
DiMaggio, Evans and Bryson (1996) found most social attitudes had not polarized. Fiorina and Abrams (2008) argued elites polarized while the public stayed moderate; Abramowitz and Saunders (2008) countered that engaged voters had polarized. False polarization, overestimating the other side's extremity, also features in the debate.
Sorting and causes
Baldassarri and Gelman (2008) and Levendusky (2009) argued partisan sorting, liberals becoming Democrats and conservatives Republicans, grew more than extremity. Proposed causes include inequality (McCarty, Poole and Rosenthal, 2006), districting, media and group polarization.
FAQ
- What is ideological polarization in simple terms?
- Politicians and voters moving away from the centre toward opposite ends.
- How does it differ from affective polarization?
- Ideological polarization is about policy positions; affective polarization is about dislike of the other party's supporters.
Sources reviewed: 2026-10-26
References
- Poole, K. T., & Rosenthal, H. (1984). The polarization of American politics. The Journal of Politics, 46(4), 1061–1079. Early roll-call measure of elite polarization.
- DiMaggio, P., Evans, J., & Bryson, B. (1996). Have Americans' social attitudes become more polarized? American Journal of Sociology, 102(3), 690–755. Tests mass attitude polarization.
- Fiorina, M. P., & Abrams, S. J. (2008). Political polarization in the American public. Annual Review of Political Science, 11, 563–588. Argues mass polarization is overstated.
- Abramowitz, A. I., & Saunders, K. L. (2008). Is polarization a myth? The Journal of Politics, 70(2), 542–555. Rebuts the myth argument.
- Baldassarri, D., & Gelman, A. (2008). Partisans without constraint: Political polarization and trends in American public opinion. American Journal of Sociology, 114(2), 408–446. Separates partisan sorting from polarization.
- Levendusky, M. (2009). The partisan sort: How liberals became Democrats and conservatives became Republicans. University of Chicago Press. On partisan sorting.
- McCarty, N., Poole, K. T., & Rosenthal, H. (2006). Polarized America: The dance of ideology and unequal riches. MIT Press. Links polarization and inequality.