This article examines the importance of the internal structural dynamics of the military in the analysis of transitions from nondemocratic rule and in democratic consolidation. The authors argues that factors endogenous to the military—including variations in the size of the officer corps, solidarity among graduating classes from the military academy, and promotional prospects—are important determinants of the political behavior of militaries. As a case study, military structure and politics during Indonesia's recent transition from nondemocratic rule and current consolidation of democracy are explored in detail. While the ongoing interaction between civilians and the military is acknowledged, systematic structural features are identified as being important for understanding the behavior of the Indonesian military between 1998 and 2001. The authors compare and contrast the study of Indonesia with other cases in the literature on transitions—including Ghana, Nigeria, Portugal, and Thailand—and discuss resulting implications for the study of transitions and consolidations.