The Political Economy of Imperial Trade Policies

During the 19th century, colonial empires expanded substantially, with at their heart flourishing trade relationships between the imperial power and its colonies. Notably, imperial powers adopted distinct commercial strategies: while some pursued an ``open door'' policy, others implemented preferential tariff regimes. This paper introduces the first comprehensive dataset documenting the trade policies of the major colonial empires from 1815 to 1960. We develop a theoretical framework that identifies three central determinants of these policies: inter--imperial competition, the progressive extension of the franchise in the imperial power and variation in imperial institutional structure. We then evaluate the model's predictions using the newly assembled dataset, and find robust empirical support for its key implications.