As the former capital of the defeated Reich, Berlin had important symbolic significance beyond its geographical location. Also of importance is the eventual solidification of Germany's division was never inevitable, nor was it predetermined. It came about as a result of incremental steps, misperceptions, and misunderstandings. In short, nobody set out to have a permanent 'Western' outpost in the middle of communist governed territory, it just turned out like that.

Of crucial importance here is that during WW2, the allies comprehensively failed to come up with concrete policies for what the occupation of post-war Germany would actually look like and how it would operate. At the 1945 Postdam conference, agreement was reached on the division of Germany into three zones (hastily expanded to four when French representations got a little bit heated about their exclusion). The post-war goals were demilitarisation, de-Nazification, de-centralisation, and democratisation, but the overarching reason for division was that it made things easier to administer. A joint administration covering the entire nation would be almost insurmountably unwieldy. Hence, the four zones where each nation would administer their own smaller section.

It was because of the symbolism I mentioned above that Berlin was divided along similar lines. In the immediate post-war years, both the Western allies and the USSR's leadership believed that division was temporary and that Germany would shortly be brought back together. These ambitions are put into question by the emerging Cold War. It's very much the case that the 'German question' is influenced by the Cold War and also influences its emergence in a form of feedback loop.

The destruction of war and the dismantling of remaining industrial resources by the occupying powers in their zones (in particular - but solely - by the USSR) caused massive economic dislocation in Germany and led to what was in large part an economic decision by the UK and USA to fuse their zones into the 'bizone' (which eventually brought in the French zone as well) with the aim of bringing a new, stabilising currency (what would become the Deutschmark). This led to a reaction from Moscow, where Stalin saw the chances of a unified, communised Germany slipping away. We then get the Berlin blockade of 1948-49, the establishment of the Federal Republic of Germany (West Germany) and in response the creation of the German Democratic Republic (East Germany).

Why do the Western allies stay in a divided Berlin, though? Because it was symbolic of their determination not to retreat, to stay strong in the face of alleged 'communist aggression', and to retain 'credibility'. Throughout the Cold War Berlin is a symbol, and most leaders realise this. But symbols matter and in the rarified atmosphere of the Cold War, credibility matters and perception is often more important than reality.

Of course, the foregoing is a very, very brief encapsulation of the situation surrounding Germany's division and the status of Berlin. There's so much more detail and nuance that it would literally take a book to cover. However, if you have further questions I'll happily try to answer them.

Malcolm

Sources

Costigliola, Frank, ‘After Roosevelt's Death: Dangerous Emotions, Divisive Discourses, and the Abandoned Alliance’,Diplomatic History, 34:1 (Jan 2010), 1-23

Harrison, Hope M., ‘Driving the Soviets up the Wall: A Super-Ally, a Superpower, and the Building of the Berlin Wall, 1958-61’, Cold War History, 1:1 (2000), 53-74

Leffler, Melvyn P. and David S. Painter (eds), Origins of the Cold War: An International History, 2nd ed (New York/London: Routledge, 2005)

Reynolds, David, From World War to Cold War: Churchill, Roosevelt, and the International History of the 1940s (Oxford: Oxford University Press, 2006)

Stivers, William, ‘The Incomplete Blockade: Soviet Zone Supply of West Berlin, 1948–49’, Diplomatic History 21:4 (1997), 569–602.

Trachtenberg, Mark, A Constructed Peace: The Making of the European Settlement 1945–1963 (Princeton: Princeton University Press, 1999)