Italian Prime Minister Silvio Berlusconi, currently chairing, today called it a day as the disagreement on fundamental matters proved too great for there to be any hope of compromise being reached.
Some of the reaction to what has happened is illuminating, particularly this one from what I assume to be a German politician:
EU Member of Parliament Klaus Haensch
"Poland and Spain have shown they are not at the level of European history."
As I wrote back in June this year, of the EU draft constitution: "... we need one, but Giscard d'Estaing's effort ain't it".