Historians of the Edwardian tariff reform movement have disagreed about its aims. This article examines the motivations of the leadership of the Tariff Reform League, which was by far the most influential organization in the tariff lobby. It argues that the League's leaders were more empire-minded than often allowed, and that it was the preferential tariff which they were most determined to promulgate and defend. Indeed, attempts by the Balfourite wing of the Unionist party to twist tariff reform away from its imperial origins were strongly resisted by the League, and the forces of protection within the organization were also carefully controlled. When the Tariff Reform League finally gave way on the issue of imperial preference in January 1913, it was not because it had suddenly ceased to be concerned about the unity of the empire. Rather, the widespread public hostility to the imposition of food duties showed no sign of diminishing, thus making it difficult to persuade a critical mass within the Unionist party that tariff reform was a politically viable strategy of imperial federation.