This dissertation examines how the state-building process relates to civil-military relations and how political influence of the military affects state's conflict behavior. By doing so, this study aims to introduce a nuanced consideration of the well-known civil-military problematique, which might be summarized as the threat the military can constitute to the polity that it is created to protect. I treat this paradox by addressing the following research questions: Why do some militaries have a qualitatively higher level of influence in politics than others? Second, how does the military's influence in politics affect a state's domestic conflict behavior? And third, how does it affect state's international conflict behavior? I develop a theory that when the military is heavily involved in the state-building process, it gains an unusual place within politics, gets itself imprinted in the DNA of the state, and gains undue political power. I name such militaries as state-builder militaries and argue that such states experience qualitatively different civil-military relations, in which the military acts as an extremely Praetorian institution. I argue that state-builder militaries would be able to insulate their political power from the democratization process that the country might experience and behave as persistent interveners in politics. I also argue that state-builder militaries would not want to retreat to their barracks as easily as predicted by the mainstream literature on military regimes. These arguments also contribute to the state-building scholarship. I present this theory by process-tracing the Turkish Military's longstanding political influence over the last 150 years. For my second and third research questions, I look at the price states pay when their militaries have undue influence on political decision-making. I argue that secessionist movements will be deterred from the military's political power and would refrain from engaging in violent secessionist strategies. I also contend that politically powerful militaries would be associated with a higher likelihood of interstate conflict initiation over territorial disputes. I find empirical support for these arguments by using large-N quantitative time-series cross-sectional research designs. The theory developed in this study regarding the impact of state-builder militaries on political development has important theoretical implications for the existing scholarship on civil-military relations, state-building, and democratization. Similarly, my findings regarding the relationship between political influence of the military and domestic and interstate conflict behavior of the state call for a nuanced consideration of the military-conflict nexus. The arguments developed in this study and its empirical findings also have policy implications regarding the political roles of the military, secessionist conflict, and interstate conflict over territorial disputes.