Hilferding moved between SPD, USPD, and back as wartime editor and finance minister

Evidence

Rudolf Hilferding (1877-1941), a politician and medical doctor, was an Austro-Marxist born in Vienna. Having been editor of the German Social Democratic paper Vorwärts (Forwards), he left the SPD to join the Independent Social Democrats (USPD) during the First World War, and was editor of their paper, Freiheit (Freedom). He later rejoined the SPD, and was a Member of the Reichstag from 1924 to 1933 and Finance Minister in 1923 and 1928-9. — Rolf Wiggershaus, The Frankfurt School, 2884