This article focuses on the early years of Federal Union (FU), the leading British federalist association created in 1938. It sets out to demonstrate that FU members heavily disagreed about the economic powers of the future Federation and that these divisions weakened the appeal of the federalist cause. Archival evidence suggests the organisation shifted from economic neutrality, favoured by allegiance to nineteenth-century liberalism, which emphasized the benefits of free trade while keeping a minimum of centralized force in order to prevent interstate rivalries from boiling over into war, to a radical advocacy of supranational planning, aimed at enforcing social rights and welfare entitlements granted to all the citizens of the member-states. This swing to the Left had several implications, including abandoning the prospect of an Anglo-American union, developing a more sympathetic attitude towards the Soviet system, and breaking ties with influential members of the British establishment who had initially lent support to FU, such as Lionel Curtis and William Beveridge. By pointing at the tension between the models of Federation Pure and Simple' and Federation Plus', this article also highlights the supple and muddled nature of federalism as an ideology.
