The Structural Power of the Middle Class and State Capacity: A Causal Analysis From Socioeconomic Stratification to Foreign Policy Performance

Abstract This study examines the causal relationship between socioeconomic stratification, the structural power of the middle class, state capacity, and foreign policy performance from an interdisciplinary perspective. While the international relations literature typically explains state behavior through systemic variables and leadership preferences, the structural impact of domestic social configurations—particularly class dynamics—on foreign policy has remained insufficiently theorized. This study aims to fill that analytical gap by positioning the middle class as a foundational mediating variable between state capacity and foreign policy performance. The analytical framework rests upon a multilayered causal chain formulated as: socioeconomic stratification → structural power of the middle class → state capacity → foreign policy performance. This chain operates through three core mechanisms: the fiscal channel, through which a broad and taxable middle class strengthens the state's financial capacity; the administrative-bureaucratic channel, through which an educated and professionally specialized middle class enhances bureaucratic quality and diplomatic capacity; and the legitimacy-stability channel, through which an institutionally integrated middle class generates political predictability and public legitimacy. Drawing on qualitative research traditions, the study offers a conceptual and causal analysis that synthesizes comparative historical-sociological inferences, political economy theory, and foreign policy analysis. The findings reveal that societies with a broad, capable, and institutionally integrated middle class demonstrate significantly stronger state capacity, which in turn enhances foreign policy performance in terms of strategic consistency, international credibility, and long-term influence. Conversely, in contexts where the middle class has contracted or become precarious, fiscal vulnerability, bureaucratic capacity deficits, and legitimacy erosion deepen simultaneously, resulting in foreign policy inconsistency and a loss of international credibility. By synthesizing political economy, comparative politics, and international relations literatures around the concept of the middle class, this study subjects the "black-box state" assumption to structural critique and places the societal foundations of state capacity at the analytical center.