How the European Union reconciles uniform regulation with legitimate diversity: towards a tighter experimentalist governance architecture

Across multiple policy domains, the EU increasingly faces the challenge of balancing uniform regulation in integrated markets with accommodating legitimate diversity among member states. Such uniform rules are crucial to preventing regulatory arbitrage, ensuring a level playing field, and fostering market integration. But diverse socio-economic conditions, institutional frameworks, and political preferences across member states demand adaptability in implementing these rules to maintain social acceptance. These contrasting pressures challenge familiar approaches to accommodating diversity such as differentiated integration, differentiated implementation, and experimentalist governance. In this paper, drawing on comparative analysis of four key regulatory domains – electricity, banking, pharmaceuticals, and competition – we argue that the EU is finding a promising solution to this widespread dilemma through a more tightly integrated experimentalist governance architecture, combining synchronic uniformity with diachronic revisability: uniform rules are applied across the EU, yet are developed and revised based on inclusive review of local implementation. This paper contributes to broader debates on EU governance by highlighting the advantages of this tighter experimentalist architecture over other approaches, showing how it ensures that uniform rules are also socially acceptable.