Local Political Context and Polarization in the Electorate: Evidence from the 2004 Presidential Election

Abstract

Political scientists have long examined the degree to which the American electorate exhibits partisan and ideological polarization and sought to explain the causal mechanism driving this phenomenon. Some scholars have argued that there is an increasing degree of geographic polarization of the electorate—that is, a large percentage of geographic units are becoming less politically heterogeneous. In this study, I argue that the two trends are related. Using individual-level data from the 2004 National Annenberg Election Survey, I examine the relationship between local partisan context and political attitudes using multilevel models. I find that, as the local political context becomes less competitive in national elections; those in the local political majority become more ideologically extreme, strengthen their partisan attachments, and hold more polarized attitudes toward the two major-party presidential candidates. These findings suggest that the growing geo- graphic partisan segregation of the electorate is an important source of ideological and partisan polarization.