London Briefing Chris JohnsAnybody who pauses to ponder on the resounding success of the eurosceptical UK Independence Party in last week's European elections needs to go all the way back to a speech made by Winston Churchill in 1946. Churchill was one of the first people, and probably the first high-profile politician, to declare himself in favour of a "United States of Europe."

Many people might be surprised to learn that such an avowed British nationalist would have nailed his colours so firmly to the federalist mast, but Churchill was a brilliant historian who understood Europe's depressing cycle of war, the centuries-long tradition that had just seen the end of France's 27th war with Germany since the 16th century.

Looking at the US, Churchill could see a model for Europe; he knew that of the 34 European countries that existed when Columbus first sighted the US, only two had managed to maintain a separate sovereign existence into the 20th century (Andorra and Monaco). The rest had been convulsed by war and revolution.

To avoid any of this happening again, Churchill and the founders of modern Europe - Schuman and Monet - knew that an integrated political structure was the only solution. But Churchill was also quite explicit: the UK had no need to have anything to do with European political unity.

That issue has dogged the UK's relationship with the continent to the present day. And it is the paradox of the success of the European project - peace has lasted - that has led to the current confusion.

Europe has achieved its objective, without full-blown political unity, but has no idea what it wants to do next. With Europe in total disarray, the sceptics can have a field day.

Nowhere is this more in evidence than with the debate over the constitution. The new European constitution is unreadable, let alone unworkable: the document that we download from the drafting body's website is over 250 pages long; a similar download of the US constitution yields a document a mere 50 pages in length, complete with the original declaration of independence and all subsequent constitutional amendments.

I defy anyone to read the constitution and come away with a sense of what Europe is actually for. The secret at the heart of the current malaise is that Europe only makes sense if full political unity is the ultimate aim; otherwise, there is no point.

Why have a constitution, to which all national law is subordinate, if Europe is merely a loose confederation of countries happy to have a free trade area? NAFTA does that for north America, without 8,000 pages of law (the length of the European statute book currently being adopted by the accession states).

A successful Doha round of WTO talks would have more economic significance than the implementation of the proposed constitution.

Tony Blair, when challenged, says that he relishes the prospect of finally having the European debate. What does he think has been happening since Churchill made his original call? What does he think people were doing when they cast their vote for Robert Kilroy-Silk?

People seek clarity and all they hear is waffle and obfuscation. Blair knows that Europe must progress to political union; he is probably in favour of it, but he cannot bring himself to make the case for Britain's participation. Instead, we have the usual nonsense about Britain being left at the station and falling behind. Just what it is we are left trailing is always unclear.

The British economy is booming; Europe's economies are limping. UK interest rates are more than double those in the euro area (which is seen as a sign of UK strength); unemployment is about half the European average. Europe spends in excess of €200 million just shuffling its pointless parliament between Brussels and Strasbourg.

The subsidy received by the average European cow is more than the per capita incomes of many Third World inhabitants.

The British electorate has not rejected Europe. They have merely thrown down the gauntlet to Tony Blair: make the case, tell us why we would be better off.

There are three dimensions to the case: the elimination of nationalist poison, the economic benefits of a proper free trade area and the security that comes with political union. The minimalist case is that the single currency requires a political union to ensure its long-run sustainability.

Schuman and Monet would despair that we have to resort to grubby economics to argue the European cause. They would know how to restate the vision to suit the modern era.

That is the challenge facing Blair.