The political consequences of elite and mass polarization

Is the American electorate ideologically polarized as its representatives are polarized in Congress? How ordinary citizens have responded to growing elite polarization? The goal of this dissertation project is to answer these two questions. I conceptualize polarization here as having multi-dimensional characteristics and distinguish between polarization as a state and polarization as a process. Based on the conceptualization of polarization, I argue here that most existing literature has not only focused on polarization as a presence, but the empirical strategies adopted by previous research are more appropriate for assessing the existence rather than gradual polarization as a process. I assume that the degree of ideological polarization among the mass public would not be dramatic, thus scholars are more likely to be divided regarding the existence of popular polarization due to the less apparent changes in public opinion distribution. Therefore, I propose here using relative distribution method to evaluate a level of opinion polarization developed in the other field of social science. Using the alternative method, we can assess how a comparison cohort of a recent period is more or less polarized compared to a reference cohort of a previous period. I first apply the relative distribution method to congressional roll-call data (DW-NOMINATE) to demonstrate the distributional comparison analysis on quantile bases. Then I analyze the cumulative American National Election Study (ANES) 1948-2008 survey to assess the relative degree of mass ideological polarization. As I analyze ideological preference of individuals, I construct the two ideological measures based on a factor analysis, rather than using a combined single indicator.

In addition to the analysis of mass opinion polarization as a whole, this dissertation also examines some political consequences of ideological polarization both at elite and mass levels focusing on mass political awareness and engagement. In particular, I also test if heterogeneous effects of polarized political environment exist on citizens conditional on their existing levels of political resources such as political knowledge or formal education. Just as many detailed characteristics of distribution might be untapped by summary measures (e.g., mean), behavior of extremists might not be explained properly by the conventional regression analysis based on conditional mean effect. While the ordinary regression analysis focuses on the representative characteristics of a majority in the sample, in polarization analysis we are more often interested in the behavior of extremists placed far from the mean. So I adopt a qunatile regression to account for potentially differential responses of the mass public to polarized politics depending on their positions in the distribution of a dependent variable.

Empirical evidence suggests that polarizing political environment has brought about many significant changes in mass political attitudes and behavior. I demonstrate that the distributional center of measures of political ideology have progressively declined in later periods, though the opinion distribution of the later periods do not dramatically exhibit a text-book style polarized distribution (e.g., bimodal distribution). In addition, I find that the majority of mass public has responded to the changing political environment by becoming politically more aware. Therefore, the overall findings of this project indicate that the electoral link between the elite and the masses became either transformed or is transforming rather than being broken as the mass public assimilate the polarized politics.