Indonesia, the world's fourth most populous country, is undergoing a profound transformation that could lead to a variety of outcomes, from the consolidation of democracy to return to authoritarianism or military rule, to radical Islamic rule, or to violent disintegration. The stakes are high, for Indonesia is the key to Southeast Asian security. The authors examine the trends and dynamics that are driving Indonesia's transformation, outline possible strategic futures and their implications for regional stability, and identify options the United States might pursue in the critical challenge of influencing Indonesia's future course.