In 1849, the frankfurt assembly offered the crown of a new german nation to:

The appropriate response is Frederick Wilhelm IV. When the progressive all-German Parliament in Frankfurt offered him the majestic crown, he dismissed it for ideological and political reasons as "unworthy." A resulting endeavor by his counselor J. von Radowitz to make a union of German rulers under Prussian initiative fizzled when joined weight by Russia and Austria.

Militarism is the answer.