Other moderate party members, including Ludwig Bamberger and Theodor Barth, left voluntarily and formed the Free-minded Union.
In 1903, the electoral unsuccessful social liberal and progressive Christian National-Social Association, led by the parson Friedrich Naumann, merged into the Free-minded Union.
The gain of the National Socials' local structures led to a development of a loose notables' association towards a members' party.
Afterwards, they formed a common parliamentary group, which was part of the pro-government imperialist Bernhard von Bülow bloc together with the Conservatives and National Liberals.
The party's own left-wing and pacifist faction, including Theodor Barth, Hellmut von Gerlach, Rudolf Breitscheid and feminist Helene Lange, were discontent with this step and left to form the Democratic Union.