Soft power has remained a contentious topic in international political research since Joseph S. Nye (Bound to Lead: Bound to Lead: The Changing Nature of American Power, Basic Books, 1990a, “Soft power,” Foreign Policy, 80, 153–172, 1990b) popularized the term in the 1990s. Many scholars have attempted to refine the definition of soft power and develop methods to measure it in subsequent research. For example, S.-H. Yun and Y. Seong-Hun (“An Overdue Critical Look at Soft Power Measurement: The Construct Validity of the Soft Power 30 in Focus,” Journal of International and Area Studies, 25(2), 1–19, 2018) and Morning Consult (Soft Power Rankings, 2024, https://pro.morningconsult.com/trackers/soft-power-rankings) discuss ways of measuring soft power in the Soft Power 30 index (McClory, J., The Soft Power 30 Report, https://softpower30.com, 2018) and the Soft Power Rankings, while S. B. Rothman (“Revising the Soft Power Concept: What Are the Means and Mechanisms of Soft Power?”, Journal of Political Power, 4(1), 41–56, 2011, https://doi.org/10.1080/2158379X.2011.556346) provides a modified soft power concept by utilizing the resources/outcomes framework and a continuous measure rather than dichotomous. Other scholars measure soft power of states, such as the work of Y. Watanabe and D. L. Mcconnell (Soft Power Superpowers: Cultural and National Assets of Japan and the United States, East Gate Books, 2008) and J. Wang (“Soft Power in China : Public Diplomacy through Communication,” in Palgrave Macmillan Series in Global Public Diplomacy, 1st ed., Palgrave Macmillan, 2011) looking at Chinese soft power changes. The challenges in understanding soft power occur at both the conceptual (theoretical) level and the empirical level. Beyond a general agreement that soft power is different from hard power, involving cooption and persuasion rather than force, few scholars agree on the conceptualization and theory of soft power. Due to these disagreements, valid measurements of the concept become idiosyncratic in single-use studies. There is a large benefit to the generalized measurement of soft power, though conceptualization remains a considerable barrier. It is within this complex and challenging context that Wu seeks to create a generalized rubric for measuring soft power in the book Measuring Soft Power in International Relations.

Measuring Soft Power in International Relations argues for the “Soft Power Rubric” as a new and unique way to measure soft power. Wu argues that soft power manifests through the interactions among individuals between nations intermingling. The first part of the book states that soft power “resides in the minds of foreigners” (Wu, I. S., Measuring Soft Power in International Relations, Lynne Rienner, 2024, 67) rather than in the hands of governments. If we accept this argument, Wu suggests that people attracted to a country are more likely to visit the place, read their literature, learn the language, watch films, and so forth In other words, people move from understanding other countries as separate to being a part of them. This sociological approach examines the disintegration of othering and how people become part of a singular group. The soft power rubric, Wu argues, is more parsimonious than other formulations when focusing on the interactions across borders. Wu’s rubric measures soft power through indicators of social integration on a continuum from watching a movie (“short term attraction”) to emigration (“long term attraction”) (p. 3). The rubric is based on the premise that people interacting changes the views of foreign countries and thus forms the “foundation of soft power resources” (p. 3).

The first part of the book reconceptualizes soft power based on Wu’s interpretation. This lays out the conceptualization of soft power as residing primarily in the hearts and minds of the public rather than being a resource of states. In addition, Part 1 presents a comprehensive review of the soft power literature to date. Part II applies the Soft Power Rubric applied to a range of cases, to show the practical use of the new measure. The section describes the rubric for the United States, India, Russia, China, and Southeast Asian countries and compares the rubric to global rankings of soft power. The discussions illustrate how scholars could use the Soft Power Rubric as a new measure of soft power for case study research.

At first, this approach seems radical, in the author’s own words (p. 163), due to the reconceptualization of soft power; however, Nye also acknowledged this approach to a dichotomous nature of measuring power in resources and behavior (Nye, J. S., “Soft Power: The Evolution of a Concept,” Journal of Political Power, 14(1), 196–208, 2021, https://doi.org/10.1080/2158379X.2021.1879572). The behavioral perspective often provides ex-post assessments, and resource approaches provide ex-ante assessments of soft power (Nye, J. S., “Soft Power: The Evolution of a Concept,” Journal of Political Power, 14(1), 196–208, 2021, https://doi.org/10.1080/2158379X.2021.1879572). While most scholars attempt to measure power through ex-ante approaches using resource measurements to understand potential power and make predictions, using the behavioral approach helps us understand the effects. Whether power is effective depends on the context, and as Wu argued in the work, having power resources (ex-ante) does not always provide the result desired (ex-post). Incorporating Wu’s behavioral aspect into our measures provides an important future direction for understanding soft power to focus more on outcomes than on resources.

Measurement theory, the theoretical basis for converting concepts into empirical data, tells us that creating new empirical measures, as Wu attempts in the book, requires careful attention to reliability, accuracy, and validity. Wu primarily deals with conceptual validity focusing on the reconceptualization and finding a corresponding proxy. G. Goertz (Social Science Concepts: A User’s Guide, Princeton University Press, 2005) comprehensively explained the conceptualization process and methods surrounding measurement validity by emphasizing the formalization of definitions to capture all elements of the concept. To accept the Soft Power Rubric as a substitute for other measures, we must also accept the reconceptualization from resources to behavioral aspects. Although Wu adds to our understanding of soft power by considering the behavioral side of the concept, it is not clear that we must exclude the resources as well. Using Goertz’s method for conceptualization and measurement more formally, future research can find measures that capture all important dimensions of the soft power concept.

Wu’s work also brings forth questions about distinguishing causes and descriptors of soft power not well addressed by scholarship. Measurement, by definition, must be descriptive of the object, or as close to it as we can come. When measuring soft power, we often face questions of causation versus description. When measuring using the Rubric, are people interacting because of soft power influence or is it describing the current state of soft power today? When soft power exists, individuals will interact more across borders through culture, visits, and so forth In some sense, there must exist some attraction to begin the interaction so something else is still there, soft power, causing the initial attraction. These problems are not unique to the Soft Power Rubric, but one that all scholars face when measuring soft power.

Overall, Wu presents a compelling case for the importance of emphasizing the behavioral side of soft power and measuring human interaction as part of the soft power concept. As Wu discusses in the text, many factors influence whether states successfully use their resources to achieve their goals. Focusing only on resources may limit the usefulness of the data in predicting outcomes. Wu’s Measuring Soft Power in International Relations advances our understanding of soft power measurement through the Soft Power Rubric, which conceptualizes soft power through cross-border human interactions and cultural exposure. Future research should focus on integrating this approach with traditional measurements while addressing its causal implications, ultimately contributing to a more comprehensive understanding of soft power in international relations.