Although it is generally thought that larger industries have greater political influence, by directly measuring the subnational importance of industries, this article suggests that it is the importance of industries within political jurisdictions, not their absolute size, that determines their domestic political leverage. Through the evaluation of Argentina’s deviations from Mercosur’s common external tariff and from intra-regional free trade, this study evidences that subnational economic interests directly influence Argentina’s trade policies. For both large and small industries, their relative importance within the provinces that they inhabit provides the political clout necessary to gain preferential trade policy outcomes.