This paper presents a theory explaining how trade policy is contingent on the development of fiscal capacity. The paper investigates the conditions under which mercantilism is adopted as a substitute for taxation when fiscal capacity is weak, when mercantilist revenue is reinvested in devel-oping fiscal capacity, and when economies endogenously abandon mercantilist practices and embrace free trade. If mercantilism is pursued when the stock of fiscal capacity is too low, the economy eventually falls into a protectionist trap, characterized by low income and low taxes. If mer-cantilism is adopted when the initial stock is large enough, then mercantilist revenue is invested in the expansion of the fiscal bureaucracy of the state. Eventually, t...