The paper argues that the collapse of the European Council Summit in Brussels on 13 December 2003 and the failure to agree the new constitutional treaty throws the Union into a major and unprecedented crisis. Attempts by many EU politicians to talk the severity of the crisis down will not help in building a rapid and effective response to it. The Laeken ambitions of a new treaty to ensure a more democratic EU closer to the people, an efficient enlarged EU and a Union with a real voice in global affairs, lie in ruins for now. And this is indeed a crisis about enlargement, since it was the new EU of 25 that, in an unprecedented manner, failed to find a compromise to finalise the two years of work spent drawing up the constitutional treaty draft. Time will tell if the current crisis is a real turning point in the Union's development or if, in the end, it will be seen as a damaging, messy but ultimately surmounted crisis. The real losers for now are political relations in the new EU; public opinion; EU debate; democracy; and the EU's role in the world. Losses will be greater still if the new treaty is never agreed.