UC Santa Barbara

The duration of political party leaders’ tenure is one of the most consequential phenomena in the political landscape. These leaders, holding key roles as primary decision makers within their respective political parties, possess substantial potential and influence in shaping the dynamics of their organizations as they accumulate greater autonomy over time. The literature has documented the variation in political party leader tenure, the underlying factors behind such variation, and the resulting consequences. However, this literature primarily centers on advanced democracies utilizing parliamentary systems and often concentrates on the impact of political party leader tenure on the dynamic relationship among political parties and the broader landscape of democracy within these nations. This dissertation builds on this literature by expanding the scope of the field by examining the tenure of political party leaders who came to office between 1980 and 2018 in 103 democratic countries and investigating the impact of political party leader tenure at the party level. I attempt to answer the following research questions. Within political parties in democratic countries, are there differences in terms of party leadership tenure? How does party leaders’ tenure vary across space and time? What drives this variation? How does a political party leader’s tenure impact the degree of power they exercise within their respective political parties? How does party leader tenure affect intra-party democracy? Chapter 1 introduces the most comprehensive dataset on political party leader tenure to this date and then examines the variation in party leader tenure across time and space. The results of descriptive analysis and survival analysis show that younger party leaders tend to have more extended terms in office, and political party leaders in established democracies also tend to enjoy longer tenures. Additionally, another interesting finding is that parliamentary and presidential systems exhibit similar patterns when it comes to the duration of political party leaders’ stay in office. Chapter 2 integrates the literature on presidentialization of politics and test whether the length of time a political party leader serves in their position can be a predictor for the level of presidentialization in their practices. Using the original dataset introduced in Chapter 1, I employ the multiple imputation techniques and mixed-effects models to test this relationship. The results show that political party leader tenure is strongly and positively related to the level of presidentialization of these leaders. The study also demonstrates that the presidentialization score of political party leaders in parliamentary systems, as well as in older political parties, tends to be lower compared to their counterparts in other systems of government and newer political parties. Chapter 3 investigates the relationship between political party leader tenure and intra-party democracy. Utilizing the dataset introduced in Chapter 1 and several mixed-effects models, I test whether the level of democracy at the party level is predicted by the tenure of political party leaders, as well as the individual-, party-, and system-level characteristics. I find that political party leaders with longer tenures, as well as leaders of political parties fall into the nationalistic category, and tend to favor less democratic organizational structure for their parties. The results also show that some factors under investigation such as party age and leaders’ age and gender do not always correlate with party leader tenure for different components of intra-party democracy.