Unbundling Polarization

67 Pages Posted: 12 Oct 2018

See all articles by Nathan Canen

Nathan Canen

University of Houston

Chad Kendall

University of Southern California

Francesco Trebbi

University of California, Berkeley - Haas School of Business; National Bureau of Economic Research (NBER)

Multiple version iconThere are 3 versions of this paper

Date Written: September 21, 2018


This paper investigates the determinants of political polarization, a phenomenon of increasing relevance in Western democracies. How much of polarization is driven by divergence in the ideologies of politicians? How much is instead the result of changes in the capacity of parties to control their members? We use detailed internal information on party discipline in the context of the U.S. Congress – whip count data for 1977-1986 – to identify and structurally estimate an economic model of legislative activity where agenda selection, party discipline, and member votes are endogenous. The model delivers estimates of the ideological preferences of politicians, the extent of party control, and allows us to assess the effects of polarization through agenda setting (i.e. which alternatives to a status quo are strategically pursued). We find that parties account for approximately 40 percent of the political polarization in legislative voting over this time period, a critical inflection point in U.S. polarization. We also show that, absent party control, historically significant economic policies, including Debt Limit bills, the Social Security Amendments of 1983, and the two Reagan Tax Cuts of 1981 and 1984 would have not passed or lost substantial support. Counterfactual exercises establish that party control is highly relevant for the probability of success of a given bill and that polarization in ideological preferences is instead more consequential for policy selection, resulting in different bills being pursued.

Keywords: Polarization, Agenda Setting, Party Discipline, Ideal Point Estimation, U.S. Congress

JEL Classification: D72, P48, H7

Suggested Citation

Canen, Nathan and Kendall, Chad and Trebbi, Francesco, Unbundling Polarization (September 21, 2018). Available at SSRN: https://ssrn.com/abstract=3253592 or http://dx.doi.org/10.2139/ssrn.3253592

Nathan Canen

University of Houston ( email )

4800 Calhoun Road
Houston, TX 77204
United States

Chad Kendall

University of Southern California ( email )

701 Exposition Blvd, Ste. 231 HOH-231, MC-1422
Los Angeles, CA 90089
United States

HOME PAGE: http://https://www.sites.google.com/site/chadwkendall/

Francesco Trebbi (Contact Author)

University of California, Berkeley - Haas School of Business ( email )

545 Student Services Building, #1900
2220 Piedmont Avenue
Berkeley, CA 94720
United States

National Bureau of Economic Research (NBER) ( email )

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

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