A Shadow of Doubt
The Potsdam Agreement established the legal framework for the occupation of Germany in the wake of World War II. According to the agreement, Germany would be formally under the administration of the four major wartime Allies—the United States, the United Kingdom, France, and the Soviet Union—until a German government acceptable to all parties would be established. The territory of Germany, as it existed in 1937, would be reduced by most of Eastern Germany thus creating the former eastern territories of Germany. The remaining territory would be divided into four zones, each administered by one of the allied countries. Berlin, which was surrounded by the Soviet zone of occupation—newly established in most of Middle Germany—would be similarly divided, with the Western Allies occupying an enclave consisting of the western parts of the city. According to the agreement, the occupation of Berlin would end only as a result of a quadripartite agreement. The Western Allies were guaranteed three air corridors to their sectors of Berlin, and the Soviets also informally allowed road and rail access between West Berlin and the western parts of Germany (see section on traffic).
At first, this arrangement was officially only meant to be a temporary administrative structure, with all parties declaring that Germany and Berlin would soon be reunited. However, as the relations between the western allies and the Soviet Union soured and the Cold War began, the joint administration of Germany and Berlin broke down. Soon Soviet-occupied Berlin and western-occupied Berlin had separate city administrations. In 1948, the Soviets tried to force the Western Allies out of Berlin by imposing a land blockade on the western sectors: the Berlin Blockade. The West responded by using its air corridors for supplying their part of the city with food and other goods in the Berlin Airlift. In May 1949, the Soviets lifted the blockade, and West Berlin as a separate city with its own jurisdiction was maintained. By the end of 1949, two new states had been created out of occupied Germany—the Federal Republic of Germany (West Germany) in the West and the German Democratic Republic (GDR, East Germany) in the East—with West Berlin an enclave surrounded by, but not part of, the GDR.
Currently West Germany is policed by local authorities, the Berlin Police Department (BDP). Though they pass anything relevant to national security, or anything weird, up to the allies, and indeed are closely supervised by occupied powers in each quarter.
Ernst Reuter is the Mayor of West Berlin, and does his best to maintain his reputation, secure foreign aid, and maintain order in his city.