There is no one single model but rather a whole set of diverging forms of flexible integration. In fact, differentiation provides a key strategic opportunity in a bigger and more heterogeneous EU. Bringing the whole notion of differentiation into disrepute makes it difficult to utilize its formative potential to the full. There is thus a necessity to dedramatise the debate and to open it up for rational arguments. One can distinguish between the following six principal forms of differentiated integration: (1) creation of a new supranational Union; (2) differentiation via established instruments and procedures; (3) intergovernmental cooperation outside the EU; (4) differentiation through opt-outs; (5) affiliation beneath full membership; (6) differentiation through withdrawal.

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