The end of World War II set the stage for the East-West confrontation known as the Cold War. With the outbreak of the Korean War, concerns over the defense of Western Europe rose. Two corps, V and VII, were reactivated under Seventh United States Army in 1950 and American strength in Europe rose from one division to four. Hundreds of thousands of U.S. troops remained stationed in West Germany, with others in Belgium, the Netherlands and the United Kingdom, until the 1990s in anticipation of a possible Soviet attack.
During the Cold War, American troops and their allies fought Communist forces in Korea and Vietnam (see Domino Theory). The Korean War began in 1950, when the Soviets walked out of a U.N. Security Council meeting, removing their possible veto. Under a United Nations umbrella, hundreds of thousands of U.S. troops fought to prevent the takeover of South Korea by North Korea, and later, to invade the northern nation. After repeated advances and retreats by both sides, and the PRC People's Volunteer Army entry into the war, the Korean Armistice Agreement ended the war and returned the peninsula to the status quo in 1953.