"The growth in the EU's powers means that it can no longer carry out integration by stealth. Measures adopted to save the eurozone impose visible political costs without immediately visible benefits, which makes it more difficult to secure popular commitment to an ever closer union.
EU decision making occurs by consensus among the governing parties of member states, but on average they represent half their electorate, and with a multi-national Parliament whose MEPs disagree in seeking national votes but agree in endorsing EU integration. The many checks built into EU decision making institutionalise a high degree of horizontal accountability; an equally strong system of vertical accountability to Europe's citizens is lacking. However, voters can invoke their power as national citizens to pass judgment on the government that represents them in Brussels. National governments thus face competing pressures to agree with governments of other countries in the European Council and to deliver satisfaction to their own electorate. In most national referendums on EU issues, a majority endorse EU agreements.
If EU powers are to expand, the project recommends that more use should be made of national referendums to test popular commitment to EU treaties. This will also require differentiated integration so that member states where majorities want more integration may proceed while those that do not can stay where they are."