The tension of the Cold War seemed to have moved from Europe to East Asia. On October 1, 1949, the People’s Republic, under Mao Zedong, was proclaimed in China.
This Communist triumph was a great shock to the United States.
Overnight, the Communist influence seemed to have extended into the very heart of Asia and onto the doorstep of occupied Japan.
The sheer physical size of Soviet Russia and China, and of their combined populations, gave a double threat to the American policy of containment. It was against this background that a full-scale war broke out in Korea.
After the Second World War, Korea north of 38th parallel had been occupied by the Russians, while south of the 38th parallel by the Americans.
As no agreement on a common government for the whole country had been reached, the Russians established a communist regime in North Korea and the Americans a western-oriented democracy in South Korea. Syngman Rhee was elected President of South Korea.
On June 25, 1950 the North Korea troops began to invade South Korea. They attempted to unify Korea and set up a communist regime for the whole nation. American military leaders had become aware of the importance of a non-communist South Korea for the defense of Japan.
When the Security Council of the United Nations condemned the North Korean aggression, on behalf of the United Nations, the United States sent large number of troops under General Douglas MacArthur to fight back the invading North Korean troops.
When the Americans advanced to the Yalu River, they met with the strong resistance of the Chinese Communist armies who drove the Americans back to the 38th parallel. The war ended in a virtual stalemate at the 38th parallel.
Finally in July 1953, with the help of the United Nations, an armistice was arranged. It was agreed to restore the status quo ante: Korea remained divided along the 38th parallel.
The effects of the Korean War were:
(i) Korea was much devastated during the war, particularly North Korea;
(ii) China was protected by a buffer state, North Korea, in her northeast;
(iii) China and the Soviet Union became close allies after the war;
(iv) The western nations had given military assistance to the United Nations to fight against aggression and the authority of the United Nations was upheld.