The Triangle between US, USSR and China
During the Cold War, animosity existed between Communism, which is represented by USSR and China, and Capitalism, which is represented by the US. However, starting from 1960, a deterioration appeared between China and USSR which is called the Sino-Soviet split. The doctrinal divergence derived from the regimes’ different interpretations of Marxism-Leninism. Then the triangle between US, USSR and China becomes unbalanced since it consists of three negative edges. As a result, the relationships within the triangle contained a latent source of stress that the network might try to resolve. “In a triangle with three negative edges, there is the possibility that two of the bodes will ally themselves against the third.” (textbook P130)
Exactly like what is said in the textbook, a surprising visit by President Nixon to China changed everything. Since Mao Zedong’s takeover in 1949, the United States had refused recognition to the communist government, but Nixon noticed the rising animosity between China and USSR. He then decided to exploit the rivalry to win advantages for the United States. The United States dropped its opposition to Chinese entry in the United Nations and groundwork was laid for the eventual establishment of diplomatic relations. As a result, the triangle becomes balanced since there is one positive edge between US and China.
Reference
http://www.ushistory.org/us/56g.asp
https://en.wikipedia.org/wiki/Sino-Soviet_split#History