Socialist Unity Party of Germany

The Socialist Unity Party of Germany (German: Sozialistische Einheitspartei Deutschlands, pronounced [zotsi̯aˈlɪstɪʃə ˈʔaɪnhaɪtspaʁˌtaɪ ˈdɔʏtʃlants] ; SED, pronounced [ˌɛsʔeːˈdeː] ) was the founding and ruling party of the German Democratic Republic (GDR) from the country's establishment in 1949 until the Peaceful Revolution of 1989. Formed in 1946 through a forced merger of the East German branches of the Communist Party of Germany and the Social Democratic Party of Germany, the SED built and ruled East Germany as a one-party Marxist–Leninist state. The SED had, at last official count in late November 1989, 2,129,250 members, or about 17% of the entire East German adult population.

The SED was structured according to democratic centralism, with authority flowing from the Party Congress through the Central Committee to the Politburo. Though the Party Congress formally held supreme authority, the Politburo and the Secretariat carried out decision-making between congresses. The SED's General Secretary wielded absolute power, often serving concurrently in key state roles. Walter Ulbricht, the party's leading figure from the early 1950s until 1971, oversaw the construction of East Germany's socialist economy and institutions, but was eventually deposed for a series of failed economic reforms aimed at raising the GDR's competitiveness, as well as a worsening relationship with the Soviets.