Causes of the Korean War: Cold War, China, and the USSR

Background: Korea's Post-War Partition

Korea won independence after the Second World War but was partitioned between Russia in the north and the United States in the south. Russia had entered the war against Japan just before the Japanese surrender in 1945, and as a result its army occupied much of Manchuria and the Korean Peninsula north of the 38th Parallel, while American forces were stationed south of it. This situation was stabilized by the Yalta Agreement, which was intended only as a temporary resolution until a Korean government could be elected.

The basis of the conflict that was to come lay not only in the distrust between the USSR and the United States, but was also fostered by underlying political contention between North and South Korea. The Russians in the north and the Americans in the south both installed political leaders who reflected their respective political and social viewpoints — leaders who each wanted to control the whole of Korea. The communist Kim Il-sung was installed as leader in the North, and Syngman Rhee was made leader in the South. Each of these leaders began "...trying to spread their influence to the other side as soon as installed in 1946" (Evanhoe).

Against the background of this internal political strife, there was a larger political and ideological conflict between capitalism and communism that formed the underlying basis for war. This was exacerbated when communists throughout the world began attempting to extend their power and influence. "North Korea's invasion followed a series of Communist advances around the world, including the 1949 revolution in China" (Kalajian).

Efforts were made to normalize the growing tension in the region, and in 1948 an attempt was made to hold elections throughout the country. This failed mainly because North Korea refused to allow voting observers while demanding full observer access to voting in the South. The result was that both North and South Korea declared victory in the election, and each declared its government the true representative of the entire Korean people. Against this background there was a growing military buildup on both sides, each government aided by its respective supporters — the Russians and the Chinese in the north, and the Americans in the south.

It is significant that the Chinese were involved militarily at this early stage. They released more than 30,000 experienced Korean troops who had been fighting with the Chinese Communists to form the core of the North Korean army (Evanhoe). The Soviet Union also provided equipment, aircraft, and tanks to bolster this force. The United States began enhancing South Korean forces as well, but to a far lesser degree.

In 1949, both US and Soviet troops left Korea, leaving only small advisory groups behind. The North Koreans believed that the United States would probably not come to South Korea's aid and decided to invade. There was a vast disparity in the forces, and North Korea possessed overwhelming military superiority. North Korea had a 90,000-strong, well-trained army — with one in three men a combat veteran — equipped with tanks, artillery, aircraft, and ships, plus a 45,000-man reserve. South Korea had approximately 50,000 men, few of whom were veterans, and most were poorly trained, equipped, and armed. South Korea had no tanks, only a few outdated 75mm artillery pieces, about two dozen 105mm artillery pieces, limited ammunition, a few LST landing craft, one patrol craft, and no combat aircraft (Evanhoe).

At the moment of invasion, the United States decided to support South Korea. The Korean War proved to be one of the most destructive conflicts of the twentieth century. Casualties were staggering: an estimated four million Koreans died, two-thirds of them civilians; Chinese casualties are estimated at one million; and over 54,000 Americans were killed, with 103,000 wounded (Korean War).