Abstract
Abstract Extant neoclassical realist scholarship has identified a range of real-world factors (e.g., state capacity, interest group pressure, strategic culture, and leadership personality) that serve as intervening variables between systemic imperatives and states’ foreign policy behavior. Despite these elaborations, the intervening variable concept remains underdeveloped. In this article, I show that neoclassical realists have lumped together three different types of causal factors under the label intervening variable: (1) moderating factors, (2) complementary factors, and (3) primary causes. Making these distinctions explicit will enable scholars to increase the analytical precision of neoclassical realist approaches, choose appropriate research designs to test them, and define more clearly the paradigmatic boundaries of neoclassical realism vis-à-vis other perspectives.