The balance of power—a notoriously slippery, murky, and protean term, endlessly debated and variously defined—is the core theory of international politics within the realist perspective. A “balance of power” system is one in which the power held and exercised by states within the system is checked and balanced by the power of others. Thus, as a nation’s power grows to the point that it menaces other powerful states, a counter-balancing coalition emerges to restrain the rising power, such that any bid for world hegemony will be self-defeating. The minimum requirements for a balance of power system include the existence of at least two or more actors of roughly equal strength, states seeking to survive and preserve their autonomy, alliance flexibility, and the ability to resort to war if need be. At its essence, balance of power is a type of international order. Theorists disagree, however, about the normal operation of the balance of power. Structural realists describe an “automatic version” of the theory, whereby system balance is a spontaneously generated, self-regulating, and entirely unintended outcome of states pursuing their narrow self-interests. Earlier versions of balance of power were more consistent with a “semi-automatic” version of the theory, which requires a “balancer” state throwing its weight on one side of the scale or the other, depending on which is lighter, to regulate the system. The British School’s discussion of balance of power depicts a “manually operated” system, wherein the process of equilibrium is a function of human contrivance, with emphasis on the skill of diplomats and statesmen, a sense of community of nations, of shared responsibility, and a desire and need to preserve the balance of power system. As one would expect of a theory that made its appearance in the mid-16th century, balance of power is not without its critics. Liberals claim that globalization, democratic peace, and international institutions have fundamentally transformed international relations, moving it out of the realm of power politics. Constructivists claim that balance of power theory’s focus on material forces misses the central role played by ideational factors such as norms and identities in the construction of threats and alliances. Realists, themselves, wonder why no global balance of power has materialized since the end of the Cold War.
Randall L. Schweller
Jonathan M. DiCicco
Power transition theory and Graham Allison’s Thucydides Trap Project are discussed in tandem with two complementary aims: to highlight theoretical and empirical contributions of the power transition research program, and to provide critical perspective on the Thucydides Trap Project. Conventional-wisdom approaches of this sort are distinguished from power transition theory, the empirical international relations theory proposed by A. F. K. Organski and further articulated and tested by generations of scholars. The theory’s central elements—national power, stages of power transition, shifts in the distribution of power, international order and the status quo—are identified and discussed, with a focus on key variables used to explain war and peace among contending states. A comparative, critical examination of the Thucydides Trap Project is used as a lens for spotlighting key empirical contributions of the power transition theory research tradition and the value of adhering to norms of scientific rigor. Opportunities for further growth and development are noted, with special attention afforded to essential features of the power transition theory research program, including the study of (1) the timing and initiation of war; (2) rising powers’ dissatisfaction with the status quo, and a possible distinction between dissatisfaction and revisionism; and (3) reducing the risk of violent, revisionist challenges.
Lars Brozus and Hanns W. Maull
Foreign policy think tanks originated in the context of the Industrial Revolution and world wars in Western industrialized countries and then spread to all parts of the globe. In the process their national orientations toward governments and their attentive national public audiences have evolved toward a global perspective. As a consequence, they also have been drawn into, and have contributed to, the debate about the future of the Western-dominated international order. What exactly makes a think tank remains contested, but there is broad agreement on the variety of functions they fulfill. They bring knowledge to power, but power also uses them to advance its political agenda. As the idealistic notion of expert knowledge as a solution to political problems has fallen by the wayside and advocacy think tanks have flourished, the interaction of think tanks with governments, the media, and the public has become politicized. In liberal-democratic countries, there is a growing trend toward competitive knowledge production by think tanks, whereas in authoritarian systems, think tanks are increasingly being used as instruments of state-controlled public diplomacy. Ultimately, think tanks have to bridge the tension between the needs of decision-makers, on the one hand, and the standards of scientific inquiry and orientation toward the common good, on the other hand. This tension cannot be resolved, but it can be made productive. For this, a strong emphasis on professional integrity will be essential.
David C. Rapoport
The Versailles Treaty ending World War I established a new international order by creating the League of Nations and, dividing the defeated empires in Europe into a number of nation-states. The overseas empires of the defeated became League of Nations mandates, which the victorious powers administered until they were sufficiently developed for “self -determination.” Ironically, the first terrorist campaign began in a victorious power’s territory when the Irish Republican Army produced the first success in global terrorist history though it did gain all territory sought. Campaigns emerged then in other mandates and overseas territories of the victorious powers but all failed. But the Atlantic Charter drawn in World War II made the self-determination principle more obligatory by pledging that the imperial territories of the defeated powers would be freed immediately. When the war was over, the victorious powers often dissembled portions of their empires. Elements not freed largely contained conflicting ethnic elements unable to agree on how to be governed. Successful terrorist campaigns materialized in those territories, and the wave ended when the energies of governments not terrorists dissipated! But most successes were incomplete because bloody tensions between ethnic divisions in the new states persisted. Important terrorist decisions helped their causes. The First Wave’s language tactics, strategy, and targets were changed and helped terrorists get less offensive media coverage and significant support from the international world, particularly the United Nations. They now described themselves as “freedom fighters” not terrorists. Assassination occurred rarely, violence was restricted to local territories and efforts to cooperate with group were abandoned. The police were the principal civilian element attacked, and warnings about attacks were often given to other civilians enabling them to seek safety.