What is the relationship between military coups and interstate conflict? In this dissertation I intend to make the following argument: leaders face two intersecting dilemmas. The first dilemma is one of civilian-military relations and we typically refer to it as the guardianship dilemma. Leaders need the armed forces to protect the state from external threats. However, armed forces are perennial challengers to a leader's tenure. Increasing the capacity of the military increases the ability to deal with external threats also increases the threat of the military as a challenger. Decreasing the capacity of the military lowers its threat to the regime but decreases its ability to fend off foreign threats. This second is at the international level. A state that increases its capabilities decreases the security of surrounding states, increasing the likelihood of militarized expansion and conflict. We refer to this condition as the security dilemma. I argue that states are locked into an ongoing struggle to balance their internal and external threats and that states with weaker relative military capability are trapped in a vicious cycle of coups and conflict. I explore this relationship using descriptive and inferential statistical modeling to demonstrate the consistency of these empirical patterns implicated by the theoretical framework.