Applying regression discontinuity designs to American political development

Students of American political development (APD) have long been interested in questions related to the development of “state capacity” in the United States. The apparent macro-level nature of those questions may appear to discourage the pursuit of micro-level causal inferences. Yet attention to causal inference is not necessarily incompatible with inquiry into macro-level phenomena. This article explores the application of a specific causal inference strategy, namely regression discontinuity design (RDD), to three questions of interest to APD scholars of state capacity. First, the article illustrates the use of a geographic RDD to estimate the causal impacts of a Reconstruction-era federal civil rights statute during the period prior to the development of significant federal state capacity. Second, it explores the possible causes of the late 19th century decline in the use of monetary rewards to motivate civil servants by using a population-based RDD to estimate the causal impacts of financial incentives on law enforcement effort and civilian compliance. Third, it illustrates an opportunity to test claims about the impacts of the growth of the “carceral state” by applying a resource-constraint RDD to estimate the causal impacts of law enforcement effort on a variety of outcomes.