David Cameron does not want the UK slams the door of the European Union. Certainly! No doubt. But continued in his eyes, can not do at any price and certainly not by loss of sovereignty. In a speech on Europe's long-awaited, Prime Minister of his Most Gracious Majesty wanted above all make a tour de force of domestic policy: strengthen the ranks of his party before the elections of 2015. In case of victory, he pledged to hold a referendum by the end of 2017 on the membership of his country to the European Union. On the one hand, it flatters most Eurosceptic Conservatives proposing instead to renegotiate the kingdom in Europe refocused on the market. On the other, he strives not to upset the business pro-British European showing its preference for maintaining the Union. But this tightrope is not without risk. The first is a domestic policy. David Cameron involves maintaining its coalition with the Liberal Democrats. Their leader and Deputy Prime Minister, Nick Clegg, has not failed to recall its commitment to the European Union and its concern for the UK economy a long debate whose outcome is uncertain about the place of the United Kingdom in the union. In doing so, the lib dems approximates the position of Ed Miliband, the leader of the Labour opposition, who denounced him as "the huge bet on the economy." The other risk is even more striking partner, first in Germany. While Angela Merkel has expressed its willingness to discuss British wishes. But German Chancellor recalled immediately a European rule of compromise. Because, as was done at the time Margaret Thatcher, David Cameron is not concerned with the common interest of building a European economic power – and necessarily political. Its vision is a Europe à la carte where you can be a member without accepting the constraints of being in the EU without the euro or the Schengen. However, if the euro crisis and the bailout of Greece used to something, it is to show the need for a closer integration of European countries, including budgetary, fiscal and financial. At least between the 17 euro countries. This is obviously not the goal of David Cameron. If it fails to reform Europe as he wishes, the risk of leaving the Union in the UK has never been higher. But a "brixit" – the "exit" British – have a greater impact for the kingdom itself for the Union.