Political structure across nations: How the dimensionality of politics affects electoral behavior.

摘要

This project examines the relationships among electoral institutions, political structure, and party and voter behavior. While the comparative literature establishes a clear link between electoral systems and political outcomes, it ignores the role played by a country's underlying political structure. I conceptualize political structure as the degree to winch political conflict in a nation is captured by a single dimension and create a new, quantitative measure of this concept, which I term "political dimensionality." I then examine the effects of political dimensionality on political and social outcomes from a cross-national perspective.;The dissertation begins by developing the method used to generate the new cross-national measure of political dimensionality. Essentially, the method determines the dimensional structure of political space through an iterative, least squares procedure. Using voter preference data, I apply the method to 81 cases from the Comparative Study of Electoral Systems and produce a quantitative measure of dimensionality for each.;Next, I develop a model predicting that majoritarian electoral systems discourage the emergence of new dimensions; because small parties are unable to exploit new issues to overcome barriers to representation, electorally entrenched parties have little incentive to take strong stances on emergent issues. Using a sophisticated empirical strategy, I find this indeed to be the case.;I then theorize that proximity voting is less likely in political systems that do not conform to a single dimension. This is true for a host of reasons, including the simple idea that identifying the most proximate party is difficult in complex political space. I again find empirical support for this prediction. I then examine the nature of representation across various dimensional constructs and electoral institutions. I find evidence that elite-voter congruence is greater in low-dimensional systems, but I do not find that the nature of representation varies across electoral systems.;The final portion of the dissertation looks in depth at two countries: Australia and Peru. The chapter on Australia finds that voters and parties are coherently located along a single dimension and that these locations are a strong predictor of vote choice. In Peru, the country's proportional electoral system has created a complex underlying political space. Using data over three elections, I examine how dimensionality and voting behavior evolved within this arena.;In sum, this dissertation provides a new measure of political dimensionality, a concept frequently mentioned in comparative political research but rarely quantified. I explore the measure's relationships with several micro and macro political factors across several countries. In the end, a clearer picture of political dimensionality across countries emerges. I find that dimensionality is dependent on a country's institutional configurations, while it also effects the behavior of parties and voters. Thus, it is important to consider the dimensionality of politics when conducting cross-national research.