Twentieth Air Force Bombardment Group, remaining at North Field, Guam as its only operational organization. In 1949, budget reductions forced the realignment and consolidation of Air Force units in the pacific, and the mission of Twentieth Air Force became the defense of the Ryukyu Islands and was reassigned to Kadena AB, Okinawa. It commanded the following units: On 27 June 1950, the United Nations Security Council voted to assist the South Koreans in resisting the invasion of their nation by North Korea. President Harry S. Truman authorized General Douglas MacArthur (commander of the US occupying forces in Japan) to commit units to the
South Korea the largest contributor of UN troops. The United States participation was critical for preventing the near defeat of the Republic of Korea by northern forces, as well as fighting back for the territory gains that define the South Korean nation today. Following the Armistice, South Korea and the U.S. agreed to a "Mutual Defense Treaty", under which an attack on either party in the Pacific area would summon a response from both. In 1967, South Korea obliged the mutual defense treaty, by sending a large combat troop contingent to support the United States in the Vietnam War. The US has