In August 1949, with the defeat of Jiang Jieshi [Chiang Kai-shek] and his government imminent, US Secretary of State Dean Acheson reports that the outcomes of the Chinese Revolution were beyond US control:

“The reasons for the failures of the Chinese National Government… do not stem from any inadequacy of American aid. Our military observers on the spot have reported that the Nationalist armies did not lose a single battle during the crucial year of 1948 through lack of arms or ammunition. The fact was that the decay which our observers had detected in Chungking early in the war had fatally sapped the powers of resistance of the Guomindang. Its leaders had proved incapable of meeting the crisis confronting them, its troops bad lost the will to fight and its Government bad lost popular support.

The Communists, on the other hand, through a ruthless discipline and fanatical zeal, attempted to sell themselves as guardians and liberators of the people. The Nationalist armies did not have to be defeated; they disintegrated. History has proved again and again that a regime without faith in itself and an army without morale cannot survive
the test of battle.

The unfortunate but inescapable fact is that the ominous result of the civil war in China was beyond the control of the government of the United States. Nothing that this country did or could have done within the reasonable limits of its capabilities could have changed that result; nothing that was left undone by this country has contributed to it. It was the product of internal Chinese forces, forces which this country tried to influence but could not. A decision was arrived at within China, if only a decision by default.

In the immediate future, our historic policy of friendship for China must be profoundly affected by current developments. It will necessarily be influenced by the degree to which the Chinese people come to recognise that the Communist regime serves not their interests but those of Soviet Russia and the manner in which, having become aware of the facts, they react to this foreign domination. One point, however, is clear. Should the Communist regime lend itself to the aims of Soviet Russian imperialism and attempt to engage in aggression against China’s neighbours, we and the other members of the United Nations would be confronted by a situation [that violates] the principles of the United Nations Charter and threatens international peace and security.”