It took until the late 1970s before China became directly exposed to the core regimes of the modern international system. Prior to that time, the Communist government in Beijing represented one of the most isolated among states, especially during the period of the Cultural Revolution, 1966-76. At the start of that catastrophic movement, the government recalled all but one of its relatively small number of ambassadors from abroad, and it had few friends among its supposedly primary reference group, the Communist states and parties. No direct air flights linked China's capital to any of the major cities of Asia. Within the UN, the numbers of governments voting against the PRC taking over the seat then held by the Chinese Nationalists rose from forty-seven in 1965, when there had been a tie vote on the issue, to fifty-seven in 1966. This figure reflected a deterioration in China's external relations as chaos on the mainland spilled over into the international sphere.
The PRC was not only politically isolated in the 1960s, it was also militarily insecure. Relations with its former ally, the Soviet Union, were moving towards crisis. In 1966 the Soviets began to transfer some of their best trained forces from Eastern Europe to the Sino-Soviet border. By 1970 some thirty Soviet divisions were in place along its whole length, including those stationed in the Mongolian People's Republic. The Soviet intervention in Czechoslovakia in 1968, the enunciation of the Brezhnev doctrine of limited sovereignty shortly thereafter, the threat of Soviet nuclear attack, and the border clashes in 1969 convinced Chinese leaders that their state was endangered by a 'hegemonic' Soviet Union, a hegemony that was enhanced by the prospects of a reduced US presence in Asia, following Washington's announced withdrawal of its forces from Vietnam. The time was ripe for a more