Description:How does policy-making trigger the institutionalization of steering capacities? This book investigates this question by tackling why the European Commission expanded competences that were intentionally limited to the specific pre-accession context prior the 2004/07 EU enlargement. Five cases studies trace the policy development from before to after enlargement. Based on a two-level functional explanation that links neo-functional and the arena of powers approaches, the author shows that member states tolerate far-reaching capacity expansions, but intervene actively if policies are expected to entail political clout that threatens to strengthen direct political relationships between the EU-level and citizens.