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.
Korean nationalism
Korean reunification (Korean: 남북통일) refers to the hypothetical future reunification of North Korea and South Korea under a single government. South Korea had adopted a sunshine policy towards the North that was based on the hope that one day, the two countries would be re-united in the 1990s. The process towards this was started by the historic June 15th North–South Joint Declaration in August 2000, where the two countries agreed to work towards a peaceful reunification in the future. However, there are a number of hurdles in this process due to the large political and economic differences between the two countries and other state actors such as China, Russia, and the United States. Short-term problems such as a large number of refugees from the North migrating into the South and initial economic and political instability would need to be overcome.