At the end of World War II, the United States, Britain, France and the Soviet Union divided defeated Germany into four occupation zones, as outlined at the Yalta Conference in February 1945 and formalized at Potsdam later that year.

Berlin, though located entirely within the Soviet-occupied zone, was divided as well, with the western part of the city in Allied hands and the east under Soviet control.

But if the agendas of the Soviet Union and its western Allies had aligned in time of war, they quickly began to diverge, particularly over the future of Germany. Led by Joseph Stalin, the Soviet Union wanted to punish Germany economically, forcing the country to pay war reparations and contribute its industrial technology to help postwar Soviet recovery.

On the other hand, the Allies saw Germany’s economic recovery as crucial to preserving it as a democratic buffer against the spread of communism from Eastern Europe, over which Stalin had consolidated into the Soviet sphere of influence.

In March 1947, after communist rebellions arose in Greece and Turkey, U.S. President Harry S. Truman announced in a speech to Congress that the United States would henceforth “support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures,” by giving them military aid. This policy, which became known as the Truman Doctrine, introduced a new era of global engagement for the United States and helped articulate the growing divide between Western democracies and the Soviet Union.

That June, U.S. Secretary of State George C. Marshall announced the European Recovery Program, known as the Marshall Plan. This economic extension of the Truman Doctrine aimed to help Germany and other European nations rebuild after the ravages of war, foster loyalty among participating states to the United States and make them less vulnerable to the attraction of communism.

Implemented in April 1948, the Marshall Plan directly opposed Stalin’s vision of the postwar world: He had hoped the United States would withdraw from Europe entirely, leaving the U.S.S.R. as the dominant influence in the region.

Over the first half of 1948, representatives from the United States, Britain and France met in London to discuss the future of Germany. As a result, the United States and Britain agreed to combine their occupied zones to create Bizonia, with the ultimate goal being a single, unified West German state incorporating the U.S., British and French-occupied zones of Germany and Berlin, with a single, stable currency.

When the Soviets learned of these plans in March 1948, they withdrew from the Allied Control Council, which had met since the end of the war to coordinate occupation policy between zones.

In June, U.S. and British officials introduced the new currency, the Deutschmark, into Bizonia and West Berlin, without informing their Soviet counterparts. Viewing this as a violation of their postwar agreements, the Soviets immediately issued their own currency, the Ostmark, into Berlin and eastern Germany.

That same day—June 24, 1948—they blocked all road, railway and canal access to the Allied-occupied zones of Berlin, announcing that the four-way administration of the city had come to an end.

With their blockade, the Soviets cut some 2.5 million civilians in the three western sectors of Berlin off from access to electricity, as well as food, coal and other crucial supplies. Though the Red Army far outnumbered Allied military forces in and around Berlin, the United States and Britain retained control of three 20-mile-wide air corridors from West Germany into West Berlin, according to written agreements with the Soviet Union from 1945.

Beginning June 26, 1948, two days after the blockade was announced, U.S. and British planes carried out the largest air relief operation in history, transporting some 2.3 million tons of supplies into West Berlin on more than 270,000 flights over 11 months.

The Berlin Blockade, and the Allied response in the form of the Berlin Airlift, represented the first major conflict of the Cold War.

While Stalin had hoped the Berlin Blockade would force the Allies to abandon their efforts to create a West German state, the success of the Berlin Airlift confirmed such hopes were in vain. By May 1949, when the Soviets lifted the blockade, the crisis in Berlin had hardened the East/West division of Germany and all of Europe, ushering in the Cold War in earnest.

The Berlin Airlift, 1948-1949, U.S. Department State: Office of the Historian.
The Berlin blockade and airlift, BBC Bitesize Guide.
Berlin Blockade, PBS: American Experience.
Benn Steil, The Marshall Plan: Dawn of the Cold War (Simon & Schuster, 2018).
Barry Turner, The Berlin Airlift: The Relief Operation that Defined the Cold War (Icon Books, 2017).