Is flexible implementation an effective and legitimate way to cope with heterogeneity in the European Union?

This policy brief brings together the findings from different studies done under Work Package 7 of the InDivEU project. Based on these studies, it formulates a number of more general conclusions and recommendations. The underlying question are how flexible implementation in the EU works and whether it can be an effective and legitimate way to cope with heterogeneity among member states. Flexible implementation allows for a more nuanced balance between EU-level cooperation and member state autonomy than differentiated integration, under which member states are either fully ‘in’ or ‘out’ of an EU-level policy arrangement. In doing so, it may contribute to the acceptance of EU policies by member states. At the same time, flexible implementation presents a trade-off between (the benefits of) flexibility and the level of ambition in an EU policy arrangement, as member states tend to use flexibility to preserve existing domestic policy arrangements. Based on this, we recommend to pay more systematic attention to the potential advantages of disadvantages of flexible implementation when proposing and discussing policy proposals. Moreover, it would be good to stimulate cross-border learning between member states, in order to enhance the innovative potential of flexible implementation