權力平衡理論之研究：現實主義的觀點

Researching the Theory of Balance of Power: A Realist View

權力平衡理論是現實主義中相當重要的一部分，是維持國際體系穩定與秩序的機制。在國家往來的歷史中，無論早期的歐洲多邊協調，還是20世紀的冷戰兩強對峙，均成為現實主義用以印證權力平衡的最佳事例。惟現實主義中不同的流派對於權力平衡是項概念在認知上存有若干差異，古典現實主義與新現實主義間基於對權力的解讀不同，從而對權力平衡形成的原因及其類型有不同的看法；而身為主流國關理論之一的新現實主義內部，也相繼提出學理上的修正或補充，用以填補學者華茲關於權力平衡論述上的疏漏。透過介紹與說明現實主義中有關權力平衡的相關論述，本文指出，新現實主義關於權力平衡理論的貢獻在於解釋了國際政治長期演進過程中一個必然的規律或傾向，從根本上解釋了權力平衡形成的原因。華茲所注重的權力平衡實際上是「體係結構的平衡」，而不是國家間「聯盟勢力的平衡」。此外，權力平衡並非制約國家權力的一種可靠方式，儘管它如現實主義所說，在國際政治上佔有舉足輕重的地位，但其理論內部的缺失與疏漏確實使其無法全面有效的解釋國家行為和扮演維護國際秩序的角色。無奈的是，強權政治（great power politics）仍充斥於國際社會的現實，使得利用權力平衡來維護國家利益或體系的相對穩定，依舊是國際政治中的一項準則。

The Balance of Power theory (BOP) is an essential part of Realism; it is a mechanism present to keep the stability and order of the international system. The review of historical interactions among states, i.e. the Concert of Europe and the Cold War, are good examples to verify the Realist approach on the BOP. The different schools of Realism, nevertheless, have their own perceptions of BOP. Classical Realism and Neo-Realism have different opinions concerning the reasons behind the emergence and the typology of BOP. Even Neo-Realism, the mainstream of international political theories has diverse voices, as well some scholars who belong to this camp have proposed academic modification and complementation to make up for Waltz's BOP theory. By introducing and explaining the BOP theories, this article points out the considerable contribution of Neo-Realism on the BOP theory; an effective interpretation of the reasons behind the existence of BOP and an explanation of the reason why the BOP is an inevitable tendency and why it unceasingly rules during the process of international relations. Waltz, a neo-realist, emphasized on the ''the balance of system structure'' rather than an allied balance among nations. Furthermore, even though the BOP plays a key role in international politics, it is yet not a reliable mechanism to control states' powers and behaviors, as well its theoretical flaws result in the failure to comprehensively and effectively explain states' behavior and maintain the international order. In the end, no matter if the BOP is a real mechanism for keeping stability and states' interests or not, it is still a principle in a world where the great power politics talk.