Dahlet and Wolf had belonged to the Bas-Rhin branch of the Radical Party, but had quit in disagreement with its policies of centralism and anticlericalism, instead establishing the Progress Party as a party for a more decentralised and moderately secular variant of Radicalism.[1] Wolf had been the chairman of a party with the same name and similar goals in the years prior to World War I.[3]
In April 1927 a party newspaper, Das Neue Elsass ('The New Alsace'), was launched after Wolf had received financial guarantees from it. The Progress Party and Das Neue Elsass obtained a moderate degree of influence in Bas-Rhin.[1]
In 1928 Dahlet became the party leader, after Wolf resigned from the party. Wolf left politics, supposedly for personal reasons, and went back to serve as a pastor of the EPCAAL. Dahlet was elected to parliament in the same year, and would retain his seat until 1940. With Dahlet as the party leader the Progress Party became more radical in its regionalist demands, albeit never straying over to the separatist camp.[1] The party won two seats in the 1929 Strasbourg municipal election.[4]