The heterogeneous nature of monetary union will increase along with enlargement - labour and goods markets therefore need flexible adjustment mechanisms. The single monetary policy is a catalyst for reforms in other policy areas. The nation states are in competition with one another to find the best solutions for economic, labour market and fiscal policies.
Successful policy solutions set a benchmark for the less successful countries. Besides the economic criteria for a successful monetary union, the European System of Central Banks should be reformed to cope with enlargement. The present structures were designed for a 15-member monetary union.