In June 1948 the Soviet Union cut every road, rail line and canal into the western sectors of Berlin, a city of over two million people deep inside the Soviet zone of Germany. The Western powers could abandon the city, try to force the blockade with tanks and risk war, or attempt something nobody had tried at that scale. They chose to fly in the city's food and coal. That choice captures the strategy that guided the West for forty years: hold the line, but do not start a war.

Containment

In 1947 Kennan published an article in the journal Foreign Affairs, signed only with the letter X, which gave the strategy its name. Containment was the American strategy of stopping the spread of Soviet power without fighting a general war. Kennan expected that a Soviet Union boxed in for long enough would mellow or crack from within. He mainly had political and economic tools in mind, such as aid, alliances and patience. In 1950 a secret planning paper known as NSC-68 pushed in a more military direction. NSC-68 called for a massive American military buildup to meet a Soviet threat it described in stark terms, and the Korean War that began that summer made the buildup happen. Kennan later complained that his idea had been turned into something more warlike than he intended.

Seen from Moscow, containment looked like encirclement: American bases, alliances and bombers ringing the Soviet Union. Soviet leaders also feared a rebuilt Germany above all, since a German invasion had cost them tens of millions of lives only a few years before.

Two Germanys and two alliances

The blockade began after the Western allies introduced a new currency, the Deutsche Mark, in their zones in June 1948, a step toward a separate West German state. The Berlin Airlift supplied West Berlin by air until the Soviets lifted the blockade in May 1949. That same year Germany formally split into two states: the Federal Republic in the west and the German Democratic Republic in the east.

In April 1949, twelve countries founded the North Atlantic Treaty Organization. NATO's core promise is that an armed attack on one member is an attack on all. The Soviet bloc formed the Council for Mutual Economic Assistance in 1949 and, in 1955, after West Germany joined NATO, a military alliance of its own. The Warsaw Pact was the Soviet led military alliance formed in 1955. In 1952 Stalin offered talks on a reunited but neutral Germany. Western leaders dismissed the offer as a trick to stop West German rearmament, and historians still debate whether it was sincere.

Revolts in the east

Soviet control was repeatedly challenged from below. In June 1953 a workers' strike in East Berlin spread across East Germany and was put down by Soviet tanks. In October 1956 Hungarians rose up, and the reform communist leader Imre Nagy announced that Hungary would leave the Warsaw Pact. Soviet troops crushed the Hungarian revolution in November 1956; about 2,500 Hungarians were killed, some 200,000 fled abroad and Nagy was later executed. The West protested but did not intervene, unwilling to risk war in the Soviet sphere.

In 1968 Czechoslovakia's new leader, Alexander Dubček, loosened censorship and promised a more humane socialism in what became known as the Prague Spring. In August, Warsaw Pact armies invaded. Soviet leader Leonid Brezhnev then set out a justification. The Brezhnev Doctrine claimed the right to intervene wherever socialism was threatened in a socialist country. Within the bloc, sovereignty had limits.

The Berlin Wall

Berlin remained the one place where people could easily walk from east to west. Roughly 2.7 million East Germans left between 1949 and 1961, many of them young and skilled. On the night of August 13, 1961, East German forces sealed the border with barbed wire, soon replaced by concrete. East Germany built the Berlin Wall mainly to stop its own people from fleeing west, though its government called it an anti-fascist protective barrier. At least 140 people died at the Wall over the next 28 years. The Wall became the most visible symbol of the Cold War.

Worked example: the Berlin Airlift

Think through the airlift as a problem in crisis management. The Soviet aim was to make the Western position in Berlin impossible and halt plans for a West German state. Driving armored convoys through would have forced Soviet troops to shoot first or back down, and either could have meant war. An airlift shifted that burden: to stop it, the Soviets would have had to shoot down unarmed cargo planes, an act of war they wanted to avoid. American and British crews flew round the clock. On one day in April 1949, aircraft landed close to 13,000 tons of supplies, and over the whole operation about 2.3 million tons arrived. One American pilot began dropping candy on tiny parachutes for children, and the press made him famous. The political effect was large. Berliners who had been enemies four years earlier came to see the Western allies as protectors, and the blockade pushed Western Europe toward NATO. Both sides had escalated, yet neither fired a shot. That pattern, firm pressure stopping just short of open war, would mark the Cold War in Europe for decades.