In 1990, this country ceased to exist after a merger.
This country was diplomatically isolated because of the Hallstein Doctrine. A 1953 uprising in this country was brutally crushed by Walter Ulbricht. Ulbricht was succeeded as leader of this country by Erich Honecker. This country's secret police force was called the Stasi. Better diplomatic relations with this country were established by Wily Brandt's Ostpolitik. In 1990, this country ceased to exist after a merger. For 10 points, name this Warsaw Pact member that built a wall around its capital, East Berlin.
This country was diplomatically isolated because of the Hallstein Doctrine.
East {Germany} [or {Ostdeutschland}; or {German Democratic Republic}; or {GDR}; or {Deutsche Demokratische}