Why EU is facing the most critical days in its history

What is the EU constitution treaty and why does it matter?

Depending on who you believe, the proposed constitution is either a manifesto for a monolithic European superstate, or a much-needed route to a more efficient, decisive EU.

The 300-page document pulls together and formalises all the successive treaties and agreements that have accumulated over the years, and draws up arrangements for the EU of the 21st century. There are 460 articles. It's not an easy read.

What are the key clauses?

If the constitution is adopted, the EU will have a new anthem, (Beethoven's Ode to Joy) a president and a foreign minister. The president would serve a 30-month term, ending the system of a six-month rotating presidency of the Council of Ministers.

The appointment of a foreign minister would finally answer the question asked by successive American presidents - "Who do I call when I phone Europe?". And a revised voting system with more majority voting and less opportunities for countries to use a veto would be introduced.

With 25 members, and more on the way, supporters of the constitution say streamlined decision-making in Brussels will be the only way to get things done. Otherwise, say "yes" campaigners, we can look forward to years of wrangling and paralysis in Brussels as 25 countries engage in perpetual horse-trading.

The constitution would also enshrine freedom of speech and religion, the right to shelter and education, and give greater power to the hitherto toothless European Parliament. The EU political brand would finally be enshrined in a formal legal document.

Who's objecting and why?

Anti-federalists see the constitution as a fast track to a much-feared United States of Europe, in which national sovereignties, long safeguarded by the veto system, will be trampled underfoot. Europe, they argue, already has its own currency, free movement within its borders and a raft of harmonised economic legislation. What is the point of going any further? Except to achieve what Euro-sceptics have always warned was being plotted in Brussels: a single European state.

Are the suspicions warranted?

Yes and no. The powers of the new EU foreign minister, for instance, will be limited by the fact that member states retain a right to "opt-out" of his policies. The president will become the recognisable "face" of the EU but will not have executive powers. So comparisons with the US President are misleading. On tax harmonisation, opt-outs for individual states will still be available.

How is the ratification process going?

It started at a brisk pace. The Lithuanians were the first to sign off, in November, after a parliamentary vote. Five others -Slovakia, Hungary, Greece, Italy and Slovenia - also ratified after parliamentary debates. Nine more are expected to do the same. But where people, not politicians, are making the decision via referendums, all bets are off. As our graphic on the front page shows, 10 countries agreed to hold a referendum. Some, such as France, out of a misplaced complacency about the result. Some because there was no political alternative - Tony Blair cut away a key Tory policy when he accepted the need for a referendum last year. Of the 10, only Spain has held a vote; 77 per cent backed the constitution in February, though turnout was only 42 per cent

In theory, all 25 members of the EU must endorse the constitution treaty for it to become effective. That seems increasingly unlikely. France may vote against the constitution on Sunday, and the Netherlands may follow suit three days later.

If that double whammy takes place, the constitution may die on its feet before a referendum in more traditionally Eurosceptic countries such as Britain and Denmark can even be held.

France and the Netherlands! Why are two founder members of the EEC wary of signing up?

France, and particularly the French left, is having a crisis of faith in the European ideal. Having enthusiastically backed EU integration, many French Socialists now believe a newly empowered Brussels will try to impose "Anglo-Saxon" working practices on the country - meaning longer hours and less security.

They also fear cheap labour from the east is undermining hard-won social protections in western Europe. Many don't like the idea of Turkey in the EU in the near future. And some French voters just want to give a bloody nose to President Jacques Chirac, whose political reputation depends on a "yes" vote.

The Dutch campaign has been dominated by immigration, worries over Turkey's possible accession to the EU, and resentment at the high level of national contributions to the Brussels coffers.

For good measure, the newer east European members of the EU, such as the Czech Republic and Estonia and Slovenia, fear the constitution is a charter for the bigger members in the west to impose their will and rig the European market.

What happens if the French and Dutch do vote "no"?

There would probably be a formal pause in the ratification process while the EU heads of government pondered their next move. There might need to be a wholesale renegotiation of the treaty, which would mean starting all over again. Tony Blair has vowed to carry on campaigning for the constitution, whatever the results in France and the Netherlands. But if both countries do vote "no", that is almost certain to be a futile exercise. The EU is entering one of the most critical weeks in its history.