Can any "nation" survive if it's fundamental, unifying principles can not be enumerated in a constitution less-than-twice the length of the US federal constitution? Does such a "nation" even deserve to exist? The proposed EU constitution runs 575-pages...The US Constitution is about 12 in the same type-face. The British survive without any written constitution forcing tradition and necessity to ride-tandem adjusting to the needs of the people and the nation.
"It will be of little avail to the people that the laws are made by men of their own choice if the laws be so voluminous that they cannot be read, or so incoherent that they cannot be understood." ---James Madison.
The EU structure is reminiscent of the ancient Holy Roman Empire of the Hapsburg; that was neither "Holy" nor "Roman". It bound a varying alliance of duchies, principality, city-states and annexed territories together; but lacked a central raison e'tat to fall-back on in times of crisis. It's smaller successor-state, the Austro-Hungarian Empire also failed in crisis during the First World War. The creation of a European "super-state" may well have to wait until the moment of crisis that will weld the various interests together. Afterall, it took the America two wars with Britain on North American-soil, followed by the internecine Civil War to get from "The United States are..." To the "The United States is...."
The EU is and will continue to be an effective trading-block and economic alliance. It is not ready to be a "State" for it has not won the heart's of it's Peoples. And it's that plurality that is a major stumbling block, even moreso than it's resentments and fears of the unaccountable nomenklatura of Brussels-based Euro-technocrats that govern over them.
