While there are certainly instances in which realist analysis is helpful, for the most part the theory ignores the changes in the system that have evolved in the twentieth century. The simple fact that few nations now feed themselves exclusively (either importing or exporting, or both) demonstrates the extent to which interdependence has evolved. The Cold War and its bipolar balance of power is often taken as a verification of the realist view. But the importance of establishing spheres of influence in terms of economic and military security was what drove the two powers' conflict. They were establishing these spheres precisely because the interrelated nature of the global system was becoming apparent to all.
A2. Austria-Hungary served the unique function of providing a balance between Slavic and Germanic interests in Central Europe. When the Austrian emperor was assassinated by a Serbian nationalist this balance, which had been quite precarious anyway, was clearly revealed to be in the process of collapsing. The German nation, long engaged in trying to establish itself as a world power, was now faced with the probability of having to defend its perceived interests in eastern Europe against those of Slavic peoples, that is, against the Russians who would, the Germans believed, attempt to take advantage of the situation to gain control of the Balkans and more of eastern Europe.