This book highlights how resource constraints and client agency impact China's patronage policy in their pursuit of regional geopolitical power. By combining for the first time the limit of great power patrons' resources and the agency of client countries, this book accentuates that the costs and uncertainty require China to be a wary patron who must adjust its patronage priorities in order to deal with geopolitical competition. Using China's patronage delivery to North Vietnam during the fierce and geopolitically competitive period of the Vietnam War, the book underscores that neighboring countries' domestic political dynamics, which are out of Beijing's control, drive costs and uncertainty, thus constraining Beijing's choices. With a wealth of historical materials, including minutes of Chinese decision-makers' conversations with foreign counterparts; selections of Chinese leaders' manuscripts; chronologies of their diplomatic, economic, and military activities; senior Chinese officials' memoirs and biographies; and declassified Chinese official documents, this book will be of interest to students and scholars of Chinese politics, history, and international relations.