The European Parliament in the Enlarged EU: Explaining Group Membership in the European Parliament

This paper examines the decisions behind group membership in the European Parliament. Following the goals ascribed to them by Strom in other settings (1990), national parties should join the largest group that matches their socioeconomic preferences. Yet, whilst explanations taking national parties as the basic unit of analysis might sometimes suffice, we argue that it is often necessary to consider the influence of individual party members and existing EP groups. The pursuit of individual and collective interests by all these actors determines the attractiveness of the various options open to a party weighing up its group affliation in the European Parliament. After developing a conceptual framework to explain the dynamics behind membership decisions, we illustrate it by reference to the attempt by the British Conservative Party to leave the European People's Party-European Democrats (EPP-ED) group, an effort ending in the formation with the Czech Civic Democrats (ODS) of an extraparliamentary federation, the Movement for European Reform