Balance of Power

The balance of power is, arguably, the most central theoretical concept in the study of international relations, yet it is also one of the most controversial concepts in the field. It is a significant concept because it underpins how theorists of a realist predisposition think about international relations, and realism is one of the most widely acknowledged general theories in the discipline. The concept is also controversial because realism, in general, and the balance of power, in particular, have always been fundamentally challenged by other schools of thought. Advocates of the balance of power argue that it helps account for the most fundamental features of international relations and, in particular, the survival and stability of any system of independent states. Critics, by contrast, attack the concept by insisting that it is either incoherent, thereby promoting a spurious understanding of international relations, or dangerous, because it promotes policies that can lead to international tensions and often war. This entry first examines the balance of power metaphor and describes its historical development. It then discusses the roles the concept has in contemporary thought, especially in the work of Hans J. Morgenthau and Kenneth N. Waltz.

The controversy that surrounds the balance of power is not a recent phenomenon. It can be traced back for several centuries, although there is no authoritative genealogy of the concept. Debates about the balance of power became a regular feature of the theory and practice of international relations in Europe from the 16th century onward. The balance of power is generally regarded as an essentially Eurocentric concept, although this assessment remains somewhat speculative because so little is known about the theory underpinning how other international societies have operated.

While the balance of power is generally regarded as a concept that is quintessentially related to international relations, it is also a concept that is regularly used across the social sciences as well as in general parlance. However, outside international relations, the balance of power is not seen to be particularly controversial. The term is employed ubiquitously because it acts as a metaphor that effectively transforms our conventional understanding of power. Unadorned, power is generally treated as an attribute that enables an agent possessing power to regulate the activities of other actors. In the literature on power, this usage is often referred to as a behavioral or agential conception of power. The balance of power metaphor transforms this conventional meaning into a structural or systemic conception of power.

When treated as a metaphor, the balance of power has been associated with a wide array of images, from a chandelier to the arch of a bridge. The image that most frequently springs to mind is a set of scales. From the perspective of international relations, the scales can be viewed as a system in which the weights that are placed on the pans of the scales are equated with the power capabilities of the states that operate within the system. What the metaphor demonstrates is that if [Page 130]the weight/power is increased in one pan, then the weight/power on the other pan is automatically affected. It follows that power must be treated as a relative rather than an absolute phenomenon. But the metaphor can also indicate that if there is a disproportionately heavy weight placed in one pan of the scales, then it is possible to establish an effective counterbalance by placing a number of lighter weights on the other pan. The even distribution of power that is then formed is often represented as the definition of a balance of power.

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