This chapter recounts the Vietnam War in the context of the Sino-Soviet competition for leadership in the global communist movement. It shows that after Nikita Khrushchev’s fall from power in October 1964, the Soviet leadership sought to build up their own revolutionary legitimacy by supporting Hanoi’s war effort. The Chinese leaders resented Soviet involvement, and tried to dissuade North Vietnam from overdependence on Moscow. However, China’s descent into the chaos of the Cultural Revolution lessened Beijing’s leverage over North Vietnam. From the late 1960s, Hanoi increasingly began to tilt in the Soviet direction, beginning a geopolitical shift that would completely reshape the region in the coming years.