South Korea–United States relations
Following Japanese surrender at the end of the Second World War, the Allied Powers divided the Korean peninsula along the 38th Parallel with two occupation zones with the United States in the south, and the Soviet Union in the north that would later become North Korea. On August 15, 1948, the southern half of Korea declared independence as the Republic of Korea with Syngman Rhee as president. The United States recognized the Republic of Korea as an independent state on January 1, 1949 and diplomatic relations between two countries were established on March 25 in the following year.
Cross-border skirmishes and raids at the 38th Parallel escalated into open warfare when the North Korean forces invaded South Korea on June 25, 1950. The Korean War broke out when North Korea invaded South Korea. In response, 16 member countries of the United Nations, including the United States, came to the defense of South Korea. It was the first significant armed conflict of the Cold War with extensive deployment of American and other troops.
History of South Korea
The two parties were unable to agree on the implementation of Joint Trusteeship over Korea. This led in 1948 to the establishment of two separate governments – the Communist-aligned Democratic People's Republic of Korea (DPRK) and the West-aligned First Republic of Korea – each claiming to be the legitimate government of all of Korea. On June 25, 1950 the Korean War broke out. After much destruction, the war ended on July 27,1953 with the 1948 status quo being restored, as neither the DPRK nor the First Republic had succeeded in conquering the other's portion of the divided Korea. The peninsula was divided by the Korean Demilitarized Zone and the two separate governments stabilized into the existing political entities of North and South Korea.