War had taken a heavy toll on Korea by the time the 2d Ranger Company arrived on the peninsula at the end of December 1950. Fighting had been going on there since North Korean forces first crossed the 38th parallel on 25 June 1950. The South Koreans, completely unprepared for the assault, were initially routed. Seoul, the South Korean capital, fell on the third day of the attack, as the South Korean Army retreated across the Han River. Meanwhile, the United Nations took action. The Security Council condemned the North Korean attack and called on member nations to send military aid to the South Korean Republic. The United States responded by sending advisors and what land, sea, and air forces it had immediately available, but it too had not been prepared for the North Korean attack. The majority of the regiments on occupation duty in Japan were poorly trained and vastly under-strength. The 7th Infantry Division was sent to Korea about forty percent strength, and utilized South Korean citizens drafted by President Syngman Rhee, who was living in exile in Japan with about one million Korean citizens. In a letter to General Douglas MacArthur dated 14 July 1950, Rhee granted him “command authority over all land, sea, and air forces of the Republic of Korea during the period of the continuation of the present state of hostilities.”12 These forces helped slow the North Korean advance and establish a defensive perimeter around the city of Pusan, at the southernmost tip of the peninsula.
The war turned decisively in favor of South Korea and the United Nations on 15 September, when the X Corps, under the direction of General Douglas MacArthur, successfully landed at Inchon. This landing placed a large American force on the Korean peninsula behind the main North Korean army fighting around Pusan, forcing the North Koreans to retreat. Once the Americans and South Koreans had battered the enemy back across the 38th parallel by the end of September 1950, the decision was made to use the momentum of success to invade the North and reunite the Koreas.
Accordingly, UN forces continued the attack across the 38th parallel, and by 25 October had pushed the North Korean army as far north as the Yalu River at the Chinese border. It looked like the war would be over before the 2d Ranger Company completed its training at Fort Benning during the last week of November 1950.
It was then that the war took a grave turn for the free world when Chinese soldiers poured across the border to engage UN forces and aid the North Koreans in their fight. At this point the 2d Rangers were nearing completion of their training at Fort Benning. The assault forced UN and US troops to retreat steadily south, and by the time the 2d Rangers arrived in Japan the troops in support of South Korea had fallen back to the Pusan Perimeter. When the Rangers arrived in Korea, the combined Chinese and North Korean army continued pushing Americans, South Koreans, and other allied forces southward on the peninsula.