The single currency and the close integration of European markets have increased the interdependencies among Member States and hence the potential for cross-border contagion. The EMU must have rules and these rules have to ensure that the policies of one Member State do not impact negatively on other Member States via the increased interdependence of their economies.
Member States must regard their economic policies as a matter of common interest and coordinate them. Together with the rules, the EMU has to be equipped with the means and the will to ensure compliance.