Sino-Soviet split
The Sino-Soviet split transformed the geopolitics of the bi-polar cold war into a tri-polar cold war, and facilitated Sino-American rapprochement and the 1972 Nixon visit to China. It ended the era of "monolithic communism. Historically, the ideological Sino-Soviet split facilitated the Marxist–Leninist "Realpolitik" by which Mao established the tri-polar geopolitics (PRC-USA-USSR) of the late-period Cold War.