24 Pages Posted: 9 Jan 2015 Last revised: 14 Apr 2015

Date Written: April 13, 2015

Abstract

Voters express varied levels of support for the parties’ candidates depending on where they live, be it in the South (Aldrich 1995; Carmines and Stimson 1989) or rural and urban sub-regions (Gimple and Karns 2006; McKee 2008). This difference is especially pronounced among Whites, leading to varying levels of polarization based on race depending on region and sub-region of the country. To investigate this variation, we develop a new national dataset of 2008 presidential election results within 169,304 precincts merged with census demographic data. We apply methods of ecological inference to these data to estimate voting patterns among racial and ethnic groups nationally, within sections of the country, and ultimately at the precinct level. We then use these estimates to derive a measure of racial polarization at the congressional district level, and use it to predict behavior among members of the U.S. House on roll call votes identified by the NAACP as being related to civil rights. We find that polarization especially affects Democratic members in these cases, as they may need to bring together coalitions of minority voters who have favorable opinions on these issues and White voters who do not.