My manuscript, forthcoming at Yale University Press, asks the question: how do leaders win power struggles in Leninist regimes? Many political scientists emphasize the importance of institutions in such regimes. Such institutionalization allegedly provides a mechanism for distributing patronage and debating policies, stipulates rules that delineate a group that selects the leadership, and prevents the military and secret police from playing a special coercive role. This book manuscript instead argues that the defining feature of one-party states is weak institutionalization. Power struggles are therefore determined by prestige and sociological ties, the manipulation of multiple decision-making bodies, and politicized militaries and secret police. Leaders with legacies as successful warfighters are especially capable of dominating such systems. Institutionalization can only explain why elites do not pointlessly and unnecessarily violate ambiguous rules, losers rarely defect from the party or resist decisions after suffering defeat, and the coercive organs never blatantly wield force against united civilian leaders. These arguments are based on a theoretically rigorous examination of the power struggles fought by Nikita Khrushchev and Deng Xiaoping.