History of South Korea
On August 15, 1948, the Republic of Korea was formally established, with Rhee Syngman as the first president. With the establishment of Rhee's government, de jure sovereignty also passed into the new government. On September 9, 1948, a communist regime, the Democratic People's Republic of Korea (North Korea), was proclaimed under Kim Il-sung. However, on December 12, 1948, by its resolution 195 in the Third General Assembly, the United Nations recognized the Republic of Korea as the sole legal government of Korea.
Declaration of war
The UN became a combatant itself after North Korea invaded South Korea on 25 June 1950, which begun the Korean War. The UN Security Council condemned the North Korean action by a 9–0 resolution (with the Soviet Union absent) and called upon its member nations to come to the aid of South Korea. The United States and 15 other nations formed a "UN force" to pursue this action. In a press conference on 29 June 1950, U.S. President Harry S. Truman characterized these hostilities as not being a "war" but a "police action".