http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2649215
Unequal Incomes, Ideology and Gridlock: How Rising Inequality Increases Political Polarization
John Voorheis
University of Oregon - Department of Economics
Nolan McCarty
Princeton University - Woodrow Wilson School of Public and International Affairs
Boris Shor
Georgetown University, Department of Government
August 21, 2015
Abstract:
Income inequality and political polarization have both increased dramatically in the United States over the last several decades. A small but growing literature has suggested that these two phenomena may be related and mutually reinforcing: income inequality leads to political polarization, and the gridlock induced by polarization reduces the ability of politicians to alleviate rising inequality. Scholars, however, have not credibly identified the causal relationships. Using newly available data on polarization in state legislatures and state-level income inequality, we extend previous analyses to the US state level. Employing a relatively underutilized instrumental variables identification strategy allows us to obtain the first credible causal estimates of the effect of inequality on polarization within states. We find that income inequality has a large, positive and statistically significant effect on political polarization. Economic inequality appears to cause state Democratic parties to become more liberal. Inequality, however, moves state legislatures to the right overall. Such findings suggest that the effect of income inequality impacts polarization by replacing moderate Democratic legislators with Republicans.
Number of Pages in PDF File: 52
Keywords: polarization, income inequality, state legislatures, ideology
JEL Classification: D63, D31, D72