From 1920 to 1930, Raumer was a member of the Reichstag for the right wing of the DVP. From June 1920 to May 1921, he was "Reichsschatzminister" (Treasury) in the cabinet of Konstantin Fehrenbach. He focused on the question of war reparations - into his tenure fell the Spa Conference of July 1920, the interruption of negotiations by the Allies in January 1921 and the occupation of Duisburg and Düsseldorf in March 1921.