After the Second World War ended in 1945, the ideological and economic divide between the U.S. and the Soviet Union plunged the world into a protracted Cold War. While helping war-torn nations rebuild and transition to capitalist democracies, the U.S. faced competing pressures of military demobilization and countering Communist expansion. To maintain the balance of power, the U.S. built up its atomic arsenal. However, its monopoly ended in August 1949, when the Soviets successfully detonated their own bomb, prompting a forty-year nuclear arms race.
The U.S. claimed early Cold War victories with the Marshall Plan to rebuild Europe, the Berlin Airlift, and the royalist victory in Greece against the Communists in their civil war (1946-1949). Still, these successes failed to prevent Soviet-supported Communist governments from establishing control in Central and Eastern Europe. The October 1949 loss of China to the Communists led by Mao Zedong followed a decades-long civil war with Chiang Kai-shek and the Nationalists. The Chinese Communist success would have more significance when war erupted in neighboring Korea the following year.
The Korean peninsula was occupied by the Japanese from 1905 to 1945. After World War II, it was divided at the 38th Parallel into Soviet and American occupation zones. On August 15, 1948, the Republic of Korea (ROK) was officially founded in the south. U.S. Army Civil Affairs/Military Government (CA/MG) units assigned to XXIV Corps provided advice and training to all levels of government, since the Japanese controlled the main positions. When the XXIV Corps was inactivated in January 1949, all that the U.S. left behind was the Korean Military Advisory Group (KMAG) of several hundred.
In September 1948, the Democratic People’s Republic of Korea (DPRK) was established in the north. While most Russian occupying forces departed, the DPRK received Soviet war equipment. For a short time, relations between North and South Korea were tense, but stable. In early 1950, DPRK leader Kim Il-Sung’s plans to reunify Korea was not objected to by either Mao or Soviet dictator Joseph Stalin.
Post-WWII demobilization, budget cuts, and overreliance on atomic weaponry had left the U.S. military unprepared for a conventional conflict. From 8.3 million Soldiers in 1945, the Army was cut down to ten understrength combat divisions, including the 7th, 24th, and 25th, Infantry and the 1st, Cavalry Divisions of the Eighth U.S. Army (EUSA) in Japan. Most infantry regiments were short a battalion, while artillery battalions had just two batteries.
Training had been neglected, and vehicles and weapons were in disrepair. Combat veterans had largely transitioned to civilian life and, following the 1948 reinstatement of the draft, were backfilled by conscripts. Lt. Gen. Walton H. Walker, Commanding General, EUSA, reported his readiness at forty percent. Lt. Gen. Matthew B. Ridgway, on the Army staff in 1950, later remarked, “We were, in short, in a state of shameful unreadiness.”
What are known today as Army Special Operations Forces (ASOF) were virtually non-existent. The last WWII Ranger battalions had been deactivated in late 1945. During WWII, U.S. Army officers advised and led guerrilla forces in the Philippines. While several of them, like Col. Wendell Fertig and Lt. Cols. Donald D. Blackburn and Russell W. Volckmann, remained on active duty, the Army largely ignored their experiences. The exception was Lt. Col. Volckmann at the Infantry School, who was charged to write guerrilla warfare manuals. The situation was no different for psychological warfare (psywar).
Army psywar had virtually been eliminated after WWII. An exception was the platoon-sized Tactical Information Detachment (TID) at the Army General School at Fort Riley, Kansas. It supported Army Field Forces exercises in the late 1940s. Overseas, a small psywar branch had been resurrected under the G-2, Far East Command (FECOM), in Tokyo, Japan, in 1947, by WWII veteran Col. J. Woodall Greene. Most significantly, Brig. Gen. Robert A. McClure, who had supervised the strategic psywar campaign in the European Theater of Operations (ETO) during WWII, remained a persistent psywar advocate. He would be assigned to the Army staff soon after the war began.
At 0400 hours on Sunday, June 25, 1950, the North Korean People’s Army (NKPA) attacked South Korea. When the DPRK ignored UN demands to withdraw, the Security Council authorized member nations to assist the ROK in repelling the invaders. Despite the poor state of the military, President Harry S. Truman had to face that aggression. General of the Army Douglas A. MacArthur, Commander, FECOM, was ordered to launch air and naval attacks against DPRK elements south of the 38th Parallel, and to deploy his forces to the peninsula. They were to protect the South Korean port of Busan for arriving reinforcements. July 7, the UN Security Council recommended the creation of a unified UN Command (UNC) in Korea. President Truman appointed Gen. MacArthur to command this, as well as FECOM, while Lt. Gen. Walton H. Walker, Commanding General, EUSA, assumed command of the combined ground forces in Korea.
The pace of the NKPA advance, coupled with the unpreparedness of U.S. forces, forced Walker to ‘trade space for time’. Heavy losses inflicted on Task Force (TF) Smith (24th Infantry Division advance elements) in early July set the tone. Overwhelming NKPA pressure forced allied forces to withdraw southward. By early August, Lt. Gen. Walker formed a 140-mile perimeter around Busan. This allowed entry of the 2nd ID, the 1st Marine Brigade, 5th Regimental Combat Team, and the British 27th Commonwealth Infantry Brigade.
This first combat phase (June to mid-September 1950) revealed a need for ARSOF. July 5, General Headquarters (GHQ), FECOM, formed a provisional Raider Company for special missions behind enemy lines. The GHQ Raiders later had significant roles at Incheon and the Chosin Reservoir. In August, EUSA established a Ranger Training Center (RTC) at Kijang, near Busan, to train a newly formed Ranger Company, to infiltrate enemy lines and attack command posts and key facilities. But, there were bigger problems.
The war had caused a major humanitarian crisis with refugees. Once Seoul had fallen, millions of displaced Koreans fled to the relative safety of the Busan Perimeter. This convinced Gen. MacArthur that he needed a Civil Affairs capability. In September 1950, he ordered his chief of Public Health and Welfare in FECOM, Brig. Gen. Crawford F. Sams, to organize an ad hoc, 60-man Civil Affairs unit, to control civilians and address disease amongst the refugees.
Meanwhile, stateside, the Army was taking measures to improve its special operations capabilities to support the war effort. U.S. Army Chief of Staff Gen. J. Lawton Collins directed the Army G-3 to establish experimental Marauder [Ranger] companies to serve in Korea, August 29, 1950, as well as a Ranger Training Center at Fort Benning, Georgia. September 1, Gen. Collins created the Psywar Division under the G-3, led by Brig. Gen. Robert A. McClure. It was to activate, train, and deploy psywar units, the first being the Tactical Information Detachment (TID) from Fort Riley, Kansas, in October.
In conclusion, the Army had been woefully ill-prepared for conventional war when it came seventy years ago, June 25, 1950. However, U.S. resolve, rapid deployment of forces, and last ditch efforts around Busan thwarted total disaster and prevented a North Korean victory in the South. The first phase of the conflict resurrected ARSOF, from the provisional establishment of Ranger, Raider, and Civil Affairs units, to rebuilding a decrepit psywar capability. Having stopped the NKPA invasion, allied forces were ready to counter-attack in mid-September 1950.
 Quotation in Clay Blair, The Forgotten War: America in Korea, 1950-1953 (New York, NY: Times Books, 1987), 29.