In early 1948, the Soviet Union attempted to force the United States, Britain, and France out of Berlin by blocking all access routes to West Berlin. West Berlin was located within the communist-controlled zone of East Germany.

What was the United States to do? If it confronted the Soviet blockade of West Berlin with military force, it could lead to armed conflict and potentially trigger a Third World War.

President Truman ordered daily airlifts of food, fuel, and other supplies to West Berlin—not just once, but every day, and to continue for as long as the Soviets maintained the blockade. This was an extremely difficult undertaking. West Berlin had a population of 2.5 million people. To supply enough food, medicine, clothing, and urgently needed coal by air alone required one plane to take off every three and a half minutes, operating nonstop, 24 hours a day.

With extraordinary determination and resolve, the Berlin Airlift continued for more than a year, with the support of Britain and France. Together, the United States, Britain, and France carried out a total of 280,000 flights, delivering 2.5 million tons of supplies.

In May 1949, the Soviet Union lifted the blockade of West Berlin, marking the failure of Stalin’s attempt to drive the United States, Britain, and France out of the city. The blockade had lasted nearly a year. The Berlin crisis changed many Americans’ views of President Truman. In their eyes, Truman was no longer indecisive; he had become a leader actively engaged in international affairs.