Why are some regions more peaceful than others? Some regions are particularly plagued by traditional power politics and political tensions, while the danger of war between major actors has significantly declined in other regions. The conventional literature would answer the question from a dyadic perspective—a region with many states with certain set of traits, such as democracy, should be peaceful. However, it is ultimately an empirical question whether the prevalence of power politics and conflict can be solely explained by the type of states and dyads in a region. I argue that the nature of international interactions is shaped by regional-level environment. Due to local security externalities, dyadic politics and conflict is dependent on conditions in a local neighborhood. More specifically, this study focuses on the role of regional-level alliance structure. A region can be situated in various types of alliance configuration depending on the climate of global geopolitics. I argue that conflict is unlikely in a region in which a global power establishes hegemonic domination through alliance ties with local states. The presence of an external global power dominating a region provides a local enforcement mechanism and reassurance for local states, which in turn reduces hostile interactions among local states. To examine how the regional-level conditions influence dyadic-level politics among local states, this paper empirical analyzes political events data (Integrated Data for Events Analysis) applying multilevel modeling, aiming at contributing to the literature by explicitly modeling the influence of regional-level variables on local politics beyond militarized disputes. Empirical analysis revealed that a regionally shared “patron” can promote peace between local states. However, the effect of regional hierarchy turned out to be indirect. Regional dominance structured by an external global power does not exert an overarching influence over an entire region by shifting the region-specific intercept. Rather, the regional-level global power domination in terms of defense pacts particularly influences powerful local states while not quite reducing hostility among minor local states. Thus, international conflict and hostility is indirectly constrained in a region under hegemonic domination by a global power. This study has empirically explored an argument that it is fruitful to go beyond a purely dyadic analysis of international conflict. The independent effect of a spatial environment means that even similar dyads may behave differently depending on the conditions surrounding them. It shows a need to reexamine some of the important findings about international conflict from a spatial perspective, taking into account macro-regional contexts within which states operate. Moreover, the introduction of regional contexts potentially would bridge a gap between quantitative studies of international conflict and area-specific studies.