Taken from Rising Tigers: The New Powers of Post-war East Asia by James Johnson (Chicago, 1985)
Following the end of the Transpacific War(or, as it is called in China, the Second Sino-Japanese War) and the defeat of Japan in 1951, a power vacuum was left in East Asia. This caused a small power struggle and attempts to gain hegemony in the region; the three main contenders for power were the United States, China, and the Soviet Union. The United States still had a major military presence in the area, and following the fall of Europe to Nazism, was trying to take a new role in world affairs. The Soviet Union, feeling isolated by their defeat in the Second Great War, felt that they needed the resources and allies in East Asia; as a result, they attempted to support Chinese communists. However, due to geographic location, China was the nation that could most easily exert influence over the region. Understanding this, both the United States and the Soviet Union attempted to influence the Chinese, who, shortly before the Japanese invasion, had been in a state of civil war between the communist and nationalist factions.
In the end, it was the United States that came out on top for influence in China due to Operation Ark Angel. In the Operation, the United States Marine Corp invaded mainland China to strike at the Japanese, which mainly involved hooking up with the Nationalists Army and supplying them with modern weapons. This allowed the Nationalists, along with the USMC, to fight the Japanese. After the war, the Nationalist faction not only had the support of much of the country, but also a supply of modern weapons and the United States Military to fall back on(although the USMC began leaving in the fall of 1951). This ultimately led to the Sino-American Joint Defense and Cooperation Treaty which was signed in 1953. However, belligerent Soviet attempts to form communist enclaves of Chinese territory lead to few boarder skirmishes between the USSR and the Republic of China. While the skirmishes were small and did little physical damage, the rift between the RoC and the USSR would not be mended easily. Relations were also hurt between the USSR and the United States, who would not publicly reconcile until the Nixon Administration.