Between 1949 and 1950, Rau was Minister for Planning of the GDR and in 1950–1952 chairman of the National Planning Commission. In this position, as the key figure of the economic development, Rau came into conflict with SED General Secretary Walter Ulbricht. In the face of an imminent economic collapse, Rau blamed the "Bureau Ulbricht" for the wrong policy. In response East Germany's old president Wilhelm Pieck renewed the old accusation of Trotskyism against Rau. In a later letter to Pieck of 28 November 1951, Rau protested at the manner in which the Secretariat usurped the Politburo by censoring his speech on economic affairs.