If we again slink out of this affair with our tail between our legs, if we cannot pull ourselves together to present demands which we are prepared to enforce by the sword, then I despair of the future of the German Reich.
Source, in full
Letter to his wife during the Agadir Crisis (1911), quoted in L. C. F. Turner, 'The Significance of the Schlieffen Plan', in Paul Kennedy (ed.), The War Plans of the Great Powers, 1880-1914 (Boston: Allen & Unwin, 1985), p. 211