Industrial location and protection: The political and economic geography of US nontariff barriers

The debate over the relationship between the location of industry and the incidence of import barriers has been miscast. Three problems call into question the findings reported in the endogenous protection literature. First, geographic concentration is widely used as a proxy for political concentration (i.e., the spread of industry across political districts), although these two variables are conceptually and empirically distinct. Second, extant measures of geographic concentration ignore the spatial relationship among units (e.g., counties or states) in which "lumpy" industries make their home, thereby often failing to detect concentration where it exists. Third, in those few studies in which political concentration receives any direct attention at all, nonmonotonic effects and interaction terms are seldom tested, despite their grounding in theories of interest group politics more generally. This article addresses all three problems. The results indicate that geographically concentrated but politically dispersed industries are the ones most likely to receive relief from imports, although a handful of very large industries benefit from being politically concentrated. The article thus reveals how to reconcile the two competing hypotheses around which one of endogenous protection theory's most enduring debates has taken shape.