This study focuses on changes in the electoral system in presidential democracies and examines presidential involvement in such changes and the resulting outcomes. As presidents need legislative support to advance their agenda, they are incentivized to shape the electoral systems used for legislative elections in favor of their parties. I argue that the president’s political resources and context—presidential powers, forms of government, and public support—affect the process and outcomes of electoral reform. Specifically, I examine whether the reform is influenced by presidential power and, second, if the reform does happen, what kinds of reforms occur and how they are shaped by the political context, such as the forms of government or public support. The existing literature concentrates on parliamentary system reforms and suggests reforms are primarily driven by parties. While parties are likely to be significant players in presidential systems, an executive who doesn't rely on the legislature's confidence represents an additional independent actor who wields crucial political powers. In fact, presidents can leverage their vetoes, decrees, and the right to call a referendum to achieve desired reforms while countering competing reforms favorable to the opposition. If the parties acknowledge the president's possession of these political means to engage in electoral reform, they may align more with the president's agenda. This power asymmetry can influence the probability and trajectory of electoral reform. However, this is not always the case if there is a minority situation that is not conducive to the president's influence or if public disapproval toward the president is high. This is the very reason why the power resources that the president has and the political context that those lie in should be considered simultaneously. The study of electoral reform is especially relevant today. The slide toward more autocratic forms of government these days was not suddenly caused by force but rather by subtle and incremental institutional reforms. This study places electoral reform within the context of democratic development and helps us understand a process that has undermined democracy.

This study focuses on how political institutions--electoral systems and legislative rules, and coalition agreement policy pledges--affect consensus in national parliaments. Two theoretical propositions are established and tested empirically. Proposition 1 contends that consensus will be higher under proportional systems of representation (PR) than under its majoritarian alternatives. Proposition 2 contends that under coalition government, legislative consensus should be higher on legislative motions lacking governing coalition commitment. Proposition 1 is tested with new legislative vote data from New Zealand and Belgium covering those countries' institutional transformations to PR. To test Proposition 2, I focus on periods of coalition government in New Zealand and Belgium after their transition to PR, and in Britain during the Conservative-Liberal Democrat coalition government.

The analysis indicates that New Zealand's electoral system change in the mid-1990s caused a significant increase in consensus, and after reform bills assigned to a select committee chaired by an opposition MP were more likely to result in a bipartisan vote outcome, consistent with Proposition 1. Belgium's institutional transformation from 1893 to 1921 coincided with a decrease in consensus on budgetary legislation. This development suggests that PR will not have a consensus inducing effect in the near-term if the adoption of PR coincides with democratization, though the adoption of PR sets the stage for consensus building over time.

Support for Proposition 2 is mixed. In post-reform New Zealand I find that confidence and supply agreements hold those parties to the agreement together when the corresponding bill comes up for a final vote. However, governing coalition commitments are not found to increase consensus in New Zealand. During the Catholic-Liberal coalition government in Belgium from 1921-23, the opposition Socialist Party was significantly more likely to oppose the government on votes approving bills prioritized in the government's post-election declaratory speech, consistent with Proposition 2. During the Conservative-Liberal Democrat coalition in Britain, government policy commitments have a limited effect on vote outcomes. This finding confirms that the effect of coalition agreements on legislative voting in an otherwise majoritarian parliamentary system will be limited.

I explore a developing dimension of party strategy, known as the issue diversity dimension, in three major sections across three different cases. First, I conceptualize and formalize a measure to measure the issue diversity dimension and its impact across mainstream and niche parties (chapter 2). I follow with a quantitative case study of the United Kingdom to determine the exact relationships between the issue diversity dimension and electoral success (chapter 3). Second, I conceptualize the potential impact of the issue diversity dimension on Japanese parties (chapter 4). I follow with a quantitative case study of how issue diversity impacts the electoral outcomes of Japanese parties (chapter 5). Third, I conceptualize the potential impact of the issue diversity dimension on the electoral success associated with radical right populist parties (chapter 6). I follow with a quantitative case study of radical right populist parties spanning several western European democracies to determine when they experience electoral success (chapter 7). Finally, I conclude with a discussion of the findings, implications, and directions for future research.

This dissertation proposes a variation in motivations for voting for left and right populist parties, respectively. It argues voting for both types of populist parties is motivate by disaffection with government policies and perceived ideological convergence - the perception that mainstream parties are essentially ideologically interchangeable on issues relevant to them. Where the pathways to populist voting diverge, however, is argued to be based on the issue type for which the voter has become disaffected. It is argued left populist voters are disaffected with the economy, while right populist voters are disaffected by cultural policies (e.g. immigration). The respective populist party types are argued to own these issue spaces, based on the frequency and fervency with which they address them, giving them authority on the matter. The dissertation explores these claims through the use of a mixed-methods design. The first part of the dissertation explores the topic through statistical analysis. The association between ideological convergence, government failure on cultural issues and right populist voting finds positive support. The association between ideological convergence, government failure on economic issues and left populist voting does not find support. This result was likely due to a lack of data and cases – something which can be remedied with more of both in the future. Case studies of the Front National in France (right populism) and Podemos in Spain (left populism) are then conducted. The French case study tests the mechanisms suggested by the theory of the dissertation to ensure that the positive association of the statistical analysis was due to the hypothesized factors. The Spanish case study test the mechanisms suggested by the theory of the dissertation to offer evidence that the relationship is functioning as hypothesized, despite the null findings of the left populism statistical model. The dissertation concludes by discussing its findings and contributions.