Twenty nations engaged in the Korean War, often considered the forgotten war, though none of them declared war on one another. Another dozen provided medical and logistical support to the United Nations troops. The United States was the primary provider of combat troops for the UN forces deployed to aid the South Koreans. When it began the United States was woefully unprepared for war. Demobilization following the Second World War and major cuts in defense spending had severely reduced all of the armed forces, with the exception of the expanding nuclear forces. The South Koreans were even less prepared, possessed no heavy weapons such as tanks, and many of its troops were of questionable loyalty to the regime of South Korean leader Syngman Rhee.
During the first year of the war the fighting swept down, up, and back down the Korean Peninsula. The capital of South Korea, Seoul, was captured by the communists, recaptured by the United Nations, taken again by the communists, and then retaken again by the UN. Bloody massacres of civilians were undertaken by both North and South Korea. Winters were bitterly cold. During the first winter of the war, South Korean officers embezzled the funds intended to pay for food for newly drafted troops, and more than 50,000 South Korean draftees died from malnutrition while retreating before the Chinese assault.