First World War, the Allied naval blockade of the Central Powers caused food shortages in Germany, and resources from German colonies in Africa were unable to slip past the blockade; this caused support to rise during the war for a that would expand Germany eastward into Russia to gain control of their resources to prevent such a situation from occurring in the future. In the period between the First and the Second World Wars, German nationalists adopted the term in their political demands for the re-establishment of the German colonial empire, which had been dismembered by the Allies at Versailles. Ratzel said that the development of a people into a society was primarily influenced by their geographic situation (habitat) and that a society that successfully adapted to one geographic territory would naturally and logically expand the boundaries of their nation into another territory. Yet, to resolve German overpopulation, Ratzel said that Imperial Germany (1871–1918) required overseas colonies to which surplus Germans ought to emigrate. Geopolitics Friedrich Ratzel's metaphoric concept of society as an organism—which grows and shrinks in logical relation to its (habitat)—proved especially influential upon the Swedish political scientist and conservative politician Johan Rudolf Kjellén (1864–1922), who interpreted that biological metaphor as a geopolitical natural-law. In the political monograph (1917; Sweden), Kjellén coined the terms (the conditions and problems of a state that arise from its geographic territory), (the economic factors that affect the power of the state), and (the social problems that arise from the racial composition of the state) to explain the political particulars to be considered for the successful administration and governing of a state. Moreover, he had a great intellectual influence upon the politics of Imperial Germany, especially with (1916; The State as a Life-form), an earlier political-science book read by the society of Imperial Germany, for whom the concept of acquired an ideological definition unlike the original, human-geography definition. Kjellén's geopolitical interpretation of the concept was adopted, expanded, and adapted to the politics of Germany by publicists of imperialism such as the militarist General Friedrich von Bernhardi (1849–1930) and the political geographer and proponent of geopolitics Karl Haushofer (1869–1946). In (1911; Germany and the Next War), General von Bernhardi developed Friedrich Ratzel's concept as a racial struggle for living space, explicitly identified Eastern Europe as the source of a new, national habitat for the German people, and said that the next war would be