Book excerpt: After Leaning to One Side traces the rise and fall of the Sino-Soviet alliance between 1949 and 1973, emphasizing tension over the Korean and Vietnam wars. Underscoring the theme of inherent conflict within the communist movement, this book shows that while that movement was an international campaign with an imposing theory and an impressive party structure, it was also a collection of sovereign states with disparate national interests. This book explains how this dissonance was further complicated by the unequal development of the Chinese and Soviet states and their communist parties, and traces some of China's actions to Mao's grasping at leadership of the communist movement after the death of Stalin.