Date of Award


Document Type

Open Access Dissertation


Political Science

First Advisor

Harvey Starr


Democratic peace theory provides theoretical and empirical arguments of the importance about democratic institutions in shaping and promoting the global order. Yet critics propose that it is the similarity of policy interests that prevent conflict between the joint democracies instead of the effects of regime types (Gartzke 1998; Oneal and Russet 1999c; Russett, Oneal and Davis 1998; Gartzke 2000). Scholars mainly question whether interests directly cause peace or interests are indirectly caused by liberal variables, such as trade or international organizations. This debate has no obvious conclusion, but it encourages students of conflict studies to pay more attention to the study of states' interests. This project does not attempt to replace the existing results of democratic peace theories; rather, the author tries to focus on the importance of policy interests while discussing the causes of militarized disputes.

The first argument emphasizes that states with similar policy interests are less likely to experience conflict onset because interest similarity brings a concept of ingroup idea and this idea will decrease possibility of militarized interstate disputes. Additionally, interest similarity needs to be considered as a critical explanatory component for the study of conflict escalation. Similar interests reduce the possibility of escalation because severe disputes will harm both parties in terms of their shared interests. Also, a high degree of interest similarity limits escalation if a conflict should occur. Nonetheless, previous research lacks strong support for a causal relationship between conflict escalation and interests. The author provides an empirical improvement by examining the effects of interest similarity on the issue of escalation.

This dissertation contains several methodological approaches, including large-N empirical analysis in order to test the maximum likelihood estimation models on how different national interests will influence states' conflict behavior. At the beginning, I carefully discuss the core value of the conceptualization of national interests and operationalize this main independent variable as dyadic interest similarity with a latent variables framework. Then, applying the generated data on relative hypothesis testing, I argue that states with similar regimes may bring peace, but national interests should create a pacifying order for the international society as well. Democratic peace theory partially explains the peace scenario in the world. A more thorough research project should bring interest similarity into discussion, which helps to explain how states with different regime types conduct their conflict behavior.