In 1947 as the Soviet Union pressured Turkey and, through guerrillas, threatened to take over Greece, he asked Congress to aid the two countries, enunciating the program that bears his name--the Truman Doctrine. The Marshall Plan, named for his Secretary of State, stimulated spectacular economic recovery in war-torn western Europe. When the Russians blockaded the western sectors of Berlin in 1948, Truman created a massive airlift to supply Berliners until the Russians backed down. Meanwhile, he was negotiating a military alliance to protect Western nations, the North Atlantic Treaty Organization, established in 1949. In June 1950, when the Communist government of North Korea attacked South Korea, Truman conferred promptly with his military advisers. There was, he wrote, "complete, almost unspoken acceptance on the part of everyone that whatever had to be done to meet this aggression had to be done. There was no suggestion from anyone that either the United Nations or the United States could back away from it."

A long, discouraging struggle ensued as U.N. forces held a line above the old boundary of South Korea. Truman kept the war a limited one, rather than risk a major conflict with China and perhaps Russia. Deciding not to run again, he retired to Independence; at age 88, he died December 26, 1972, after a stubborn fight for life. .