Deepening is the process linking the Member States more closely together by consolidating and developing what binds them (a term also used frequently is "integration"). The customs union, the common market and related policies, and then the Euro area form part of this dynamic.
Deepening has often been presented as a prerequisite for the enlargement of the Union.


Double majority

With a view to Europe's enlargement, solutions have been put forward for maintaining the current balance between "large" countries and "small" countries in Council decision-making. One of the solutions proposed is to require that a majority be obtained of the votes cast within the Council and that these votes represent a majority of the population of the Union. The December 2000 Intergovernmental Government in Nice adopted a Protocol on the enlargement of the European Union providing that, from 1 January 2005, when a decision was to be adopted by the Council by a qualified majority, a member of the Council could request verification that the Member States constituting the qualified majority represented at least 62% of the total population of the Union.

Qualified majority
Weighting of votes in the Council