The Korean War began on June 25, 1950, when North Korea, led by Kim Il-sung and supported by the Soviet Union, launched a surprise attack on South Korea. The aim of the North Korean invasion was to unify the Korean Peninsula under communist rule. South Korea, with President Syngman Rhee at the helm and backed by the United States and other Western countries, sought to defend its capitalist and democratic ideals.

The United Nations Security Council, in a response led by the U.S., swiftly condemned the attack and called for an immediate withdrawal of North Korean forces. With the Soviet Union at the time boycotting the Council due to the absence of the People's Republic of China, the resolution passed unopposed. As a result, a multinational force, primarily composed of U.S. troops, was assembled to aid South Korea.

Initially, the North Korean forces made significant progress, swiftly capturing Seoul, the capital of South Korea, within three days of the invasion. The South Korean and U.S. forces, however, managed to establish a defensive perimeter around the southeastern city of Pusan, effectively preventing the complete takeover of the peninsula. This marked the beginning of a grueling and protracted conflict that would endure for three years.