Hans Delbrück (1848-1929), a public conservative intellectual, lived during the time of the Weimar Republic. He published a lot of articles for several newspapers and was involved in the following three major political debates: Firstly he made as a 'Vernunftrepublikaner' several proposals to bring the new republic to a success, even though he was still convinced of the Prussian-German monarchy. Secondly he researched the war guilt question, harshly criticized the assumption that Germany was the only guilty state and pleaded for a fair-minded approach to reach a reconciliation with all European nations. Thirdly Delbrück rejected as a protagonist the stab-in-the-back legend and proved as a leading military (civil) historian that Germany suffered a military defeat different to the general claim. In contrast to the radical proposals from the political left and right, Delbrück started with these alternative explanations a fruitful debate to strengthen the young German republic.