Merger of the KPD and SPD into the Socialist Unity Party of Germany

The merger of the Communist Party of Germany (German: Kommunistische Partei Deutschlands, KPD) and the Social Democratic Party of Germany (German: Sozialdemokratische Partei Deutschlands, SPD) into the Socialist Unity Party of Germany (German: Sozialistische Einheitspartei Deutschlands, SED) occurred on 21 April 1946 in the territory of the Soviet occupation zone: it is also called the forced merger of the KPD and SPD. In the course of the merger, about 5,000 Social Democrats who opposed it were detained and sent to camps and jails.

Among circles of the workers' parties KPD and SPD there were different interpretations of the reasons for the rise of the Nazis and their electoral success. A portion of the Social Democrats blamed the devastating role of Communists in the final phase of the Weimar Republic. The Communist Party, in turn, insulted the Social Democrats as "social fascists" ("Sozialfaschisten"). Others believed that the splitting of the labour movement into the SPD and KPD prevented them effectively opposing the power of the Nazis, made possible by the First World War.

In 1945 there were calls in both the SPD and KPD for a united . The Soviet Military Administration in Germany initially opposed the idea because they took it for granted that the Communist Party would, under their guidance, develop into the strongest political force in the Soviet occupation zone. However, the outcomes of the elections conducted in Hungary and Austria in November 1945, and especially the poor performance of the Communist parties, demonstrated the urgent need for a change of strategy by the Communist party. Both Stalin and Walter Ulbricht recognized the "Austria hazard" („Gefahr Österreich“) and launched in November 1945, a campaign to enforce a unification of the two parties in order to secure the leading role of the Communist party.

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