How Does the EU Reconcile Uniform Regulation with Legitimate Diversity?

There is widely believed to be a trade-off between uniform regulation – needed to manage interdependencies and externalities in integrated markets – and accommodation of legitimate diversity in preferences and conditions among participating units – needed to sustain social acceptance of any integrated regime. Within the EU, this uniformity-diversity dilemma is often seen as fueling differentiated integration – rules which apply to some member states but not others – or even disintegration, as in the case of Brexit. Such pressures for more uniform rules in particular sectors – to prevent regulatory arbitrage and ensure a level playing field – likewise challenge classic experimentalist governance architectures, in which member states are given substantial autonomy to pursue common goals in ways adapted to their local contexts. Yet our own recent research on EU financial and energy regulation shows that the Union is finding a promising solution to this widespread dilemma through the development of simplified experimentalist architectures, based on a novel combination of synchronic uniformity with diachronic revisability (Zeitlin & Rangoni 2023). In such architectures, rules and procedures may be progressively specified and discretion for lower-level actors at any given moment narrowed, but the rules and procedures remain contestable in light of local application. Our findings further suggests that member states can accept such uniform rules and practices as legitimate, provided that they can be regularly revised based on local implementation experience through deliberative review processes in which national officials themselves participate. In this paper, we will analyze the core features of this simplified experimentalist architecture and how they contribute to resolving the uniformity-diversity dilemma, drawing on our previous research on EU financial and energy regulation and exploring how far similar governance architectures may also be emerging in other regulatory policy domains, such as competition, chemicals, and pharmaceuticals.