The Copenhagen criteria define the common ground of the future European Union. Integrating countries is, however, about far more than simply defining common ground. Economic integration is crucial, as the very stability of the large monetary union hinges on economic cohesion.
A monetary union can only be stable over the longer term if - as the Treaty states in Article 121 - “a high degree of sustainable convergence” is achieved. I would like to present my view of what a “high degree of sustainable convergence” is. “Sustainable convergence” encompasses all three types of convergence: nominal convergence, real convergence and structural convergence.