In recent years, China has played an increasingly significant role in international affairs, wielding its economic and political strength to solidify its position as a global power. Within its immediate neighborhood, however, Chinese influence is not new. Chinese actions have affected how the Indian and Pakistani states have perceived and responded to domestic governance and security challenges since the early days of independence. Connecting international politics with domestic security, Harrison Akins shows how India and Pakistan’s engagement with China has shaped the two governments’ policies toward their strategic frontiers over the past seventy years. He focuses on northeastern India and Pakistan’s Balochistan Province, peripheries that have been at the center of both countries’ relationships with China and that continue to present pressing security and development challenges. In contrast to the conventional focus on state-to-state relations, Akins emphasizes frontiers and their ties to central governments. He demonstrates that China’s presence spurred the Indian and Pakistani governments to assert their sovereignty over these border regions, exacerbating conditions that led to the outbreak of antistate violence. Featuring comprehensive research and keen analysis, Adversary and Ally offers new insights into the pressures confronting South Asian governments and the limits of China’s reach.