High Quality Content by WIKIPEDIA articles! The Socialist Unity Party of Germany (German: Sozialistische Einheitspartei Deutschlands, SED) was the governing party of the German Democratic Republic from its formation on 7 October 1949 until the elections of March 1990. The SED was a communist political party with a Marxist-Leninist ideology. In the 1980s, the SED rejected the policies of Soviet leader Mikhail Gorbachev, such as perestroika and glasnost, maintaining its control over economics, personal liberty and the freedom to travel.