Managing Heterogeneity in the EU: Using Gas Market Liberalisation to Explore the Changing Mechanisms of Intergovernmental Governance

Abstract: Since the Single European Act the EU has brought many ‘public’ policy sectors characterised by heterogeneity under the umbrella of the Single Market. Consequently, some of the tools employed to shelter these sectors from supranational governance — unanimous decision-making, limited Commission competence and ‘ring fenced’ national regimes — are no longer fully relevant. The member states and the Commission have therefore developed a series of additional measures to accommodate heterogeneity. The central questions here are: as integration proceeds, what can member states reasonably demand in order to safeguard their interests? And, how can the Commission offer the necessary flexibility? The literature on policy implementation and differentiated integration provides a point of departure for generalisations about changes to mechanisms of intergovernmental governance. The present paper uses developments in the EU gas sector to explore and elaborate how the adoption of new measures changes the mechanisms of intergovernmental governance.