By 1950, the occupation of the defeated German Reich by the Allied Armies had—as could perhaps have been foreseen—begun to fracture into new alliances. Germany had been divided into four Zones of Occupation, each assigned to the four main victorious powers: the USSR, France, Great Britain and the United States. A series of elections within the broad zones, marred by the Soviet authorities’ unwillingness to recognize the Social Democratic Party—claiming it had been absorbed by the Communist-backed Socialist Unity Party—led to the USSR delegation walking out of the Allied Control Council in Berlin in March 1948. Backed by the Soviet Union—which controlled the largest area of defeated Germany (but with the second-largest population)—a blockade of Berlin began on 1 April and lasted until 30 September 1949.