The essence of realism is its attention to the exercise of power through which political actors pursue their goals of realizing desirable consequences. From the realist point of view, political actors aim at either maintaining or altering the status quo by getting others either to do what they otherwise would not do, or to refrain from doing what they otherwise would do. In other words, power relations and prudent actions are at the core of realism. The primary purpose of this article is to examine why this realist school of international relations went through changes of its analytical foci from the Interwar Era to the Nuclear Era in the twentieth century.
The realism of the Interwar Era found its target of criticism in liberalism, which totally ignored the conflict of interests among major powers over the status quo. E. H. Carr in particular severely criticized the liberal defense of the status quo. Then, the ideological confrontation between the two crusading superpowers during the Cold War directed the realist research to the misperception of intentions. Hans Morgenthau, for instance, fully understood the seriousness of the security dilemma in the Cold War context, in which the intention of the liberal United States was naturally misperceived by the Soviet Union as demanding for change of the status quo in her favor and this misperception exacerbated the prospect for negotiated settlement of conflicts. Finally, the nuclear arms race during the Cold War generated awareness among realists that the avoidance of total nuclear war was in common interests between the Cold War rivals. In this context, realists came to be aware of not only the risks of misperceived threats but also those of misperceived promises among states. This article stresses that Yoshikazu Sakamoto, placed in a proper historical context, should be re-read as one of the few Japanese scholars of international politics, who chose to theoretically tackle contemporary American realist questions, often associated with Hans Morgenthau and Thomas Schelling.