The alliance, whose details have been outlined in the previous chapter, tied the PRC into an uneasy dependence on the Soviet Union. Born of necessity and joined under conditions of distrust, the alliance provided Mao with a security treaty against an attack by the United States, in return for which he had to recognize the independence of Mongolia and to concede a whole set of special privileges for the Soviet Union in Manchuria and Xinjiang, more even than that exacted by the Tsars. Such hopes that the PRC leaders may have entertained about conquering Taiwan were shattered by the American decision to protect the island immediately upon hearing of the attack by North Korea upon the South. Having been manoeuvred in to agreeing to Kim Il-Sung’s plans to annex the South by fore, Mao found that he had to intervene to support the North once the American-led UN forces crossed into the North and approached the Chinese border. He prevailed over doubting colleagues on the grounds that the incipient challenge to China’s security and the survival of the revolution had to be met. That , together with the economic embargo announced by Truman, at the same time as the decision to protect Taiwan, placed China in the forefront of the Cold War in Asia as the main target for American isolation and containment, which was to last for the next twenty years.