 Following the First World War, he co-founded the liberal German Democratic Party, served as a member of its national board, and was elected to the Weimar National Assembly.From 17 April to 20 June 1919, he served in the cabinet of Philipp Scheidemann as Federal Minister of Finance and Vice Chancellor.He was a member of the Reichstag, representing the German Democratic Party, from 1920 to 1930.