In Challenging Inequality: Variation Across Postindustrial Societies, Evelyne Huber and John D. Stephens examine the causes of rising income inequality in Western democracies. Building on the existing literature, they start by attributing the overall increase in income inequality to technological change and globalization, which are treated as exogenous “structural” processes that apply equally to all postindustrial societies. They then focus their attention on explaining why this increase in income inequality has manifested itself differently in different countries (e.g., larger increases, or more top-heavy increases, in some countries compared with others).

To explain these differences, the authors propose an “updated version of power resources theory” (3). Specifically, they focus on the “organizational and legal-institutional strength of labor and of left parties” (14). In line with their previous work, they identify “prolonged left incumbency” (19) as a key factor mitigating—through its impact on welfare generosity—the unequal consequences of technological change and globalization. Union strength, through wage coordination and resistance to proposed cuts to social and welfare spending, also plays a key role in their analysis. Using linear multivariate regressions, they show that, in suppor