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‘As the EU takes steps to strengthen its economic and political union, it is likely to drive a deeper wedge between core eurozone states and member states outside of the common currency that are unwilling to go along. Officials in Brussels have suggested that tensions caused by tighter coordination in the common currency area can be addressed by developing new forms of what is known as two-speed or multi-speed integration, whereby core groups of countries move ahead with deeper union on certain policies, while others opt out. Although this flexible approach has worked in the past, including for the establishment of the eurozone itself, there are reasons to believe it may be less tenable today as the EU moves toward an unprecedentedly close economic, fiscal, and political union. Flexible, à la carte approaches will not by themselves resolve the tensions between the countries committed to deepening their union and those refusing to take part’.