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.
Korean War
Postwar recovery was different in the two Koreas. South Korea stagnated in the first postwar decade. In 1953, South Korea and the United States signed a Mutual Defense Treaty. In 1960, the April Revolution occurred and students joined an anti-Syngman Rhee demonstration; 142 were killed by police; in consequence Syngman Rhee resigned and left for exile in the United States. Park Chung-hee's May 16 coup enabled social stability. In the 1960s, prostitution and related services represented 25 percent of South Korean GNP. From 1965 to 1973, South Korea dispatched troops to Vietnam and received $235,560,000 in allowance and military procurement from the United States. GNP increased fivefold during the Vietnam War. South Korea industrialized and modernized. Contemporary North Korea remains underdeveloped. South Korea had one of the world's fastest-growing economies from the early 1960s to the late 1990s. In 1957 South Korea had a lower per capita GDP than Ghana, and by 2010 it was a developed country and ranked thirteenth in the world (Ghana was 86th).