George Marshall’s failed mission to mediate a coalition agreement between the ruling Nationalist government and the Chinese Communist Party (CCP) was followed by the Civil War that ended with the founding of the People’s Republic of China in October 1949 and the Sino-Soviet alliance a few months later. In less than a year, the new Communist regime was faced with a graver challenge with the outbreak of the Korean War in 1950. This time, the responses of the United States and Communist China put the two already unfriendly countries on a collision course when the Chinese military and the American-led United Nations Command forces met face to face on the Korean battlefield. One year after fierce fighting, the Americans and the Chinese Communists agreed to meet at the negotiation table to talk about an armistice, however reluctantly, as the war stalled on the battlefields. With battle and negotiation, the Chinese Communists began to build a resume showing both persistence and bargaining capacity, while the Americans learned to consider cultural factors in future diplomatic and military operations in dealing with the Communists. In the long run, Sino-US relations were built mostly through negotiations and reconciliations.

The Korean War broke out on June 25, 1950, when the North Koreans attacked South Korean positions along the 38th Parallel, and ended with an armistice three years later. The United States’ instantaneous involvement in the war to lead the United Nations Command (UNC) on the side of the Republic of Korea (ROK, South Korea) and Communist China’s entry into the war four months later to aid the Democratic People’s Republic of Korea (DPRK, North Korea) transformed the war from a civil war to an international conflict.