By Gideon Rachman

I am ready to retire as a eurosceptic. The European Union is in trouble. But rather than smirking – which would be the normal reaction of a sceptic – I am alarmed.

In January 2001, I arrived in Brussels with several firm and unfavourable convictions about the EU. I believed that most ordinary Europeans felt far more loyalty to their nation than to Europe. I thought that steadily enlarging the powers of Brussels was undemocratic and dangerous. I reckoned that in a crisis, nationalist instincts would come to the fore. I suspected that the EU's new currency – the euro – was liable to run into trouble. And I believed that the Brussels-based elite was a "new class" that had confused its own interests with those of the continent of Europe.

Eight years on, I look back at these old prejudices – and smile at my foresight. The past few years have provided a graphic demonstration of the feeble popular support for the European project. A proposed EU constitution was rejected in referendums in France and the Netherlands – then promptly repackaged as the Lisbon treaty and rejected again, this time by the voters of Ireland. But "Lisbon" will still be shoved through, one way or another. This is a pretty shoddy exercise.

The strain of the economic crisis is indeed opening up divisions within the Union. An emergency EU summit was called this weekend to combat protectionism. Several of the new EU members from central Europe are facing banking and financial crises – and the older members have refused to bail them out. The Hungarian prime minister warns of a "new iron curtain" descending across Europe. Robert Zoellick, president of the World Bank, is worried that Europe is once again splitting into two.

Arguably, all my darkest suspicions about the European project are about to be vindicated. So it is an odd time to renounce euroscepticism.

But it is precisely the threat to the EU that has focused my mind. Plans for a political union in Europe were always crazy. But the four freedoms already established by the EU – free movement of goods, people, services and capital – are huge and tangible achievements. It would be terrible to see them rolled back.

Yet the threat is there. The British prime minister has talked of "British jobs for British workers", the French president has urged car companies to invest at home rather than elsewhere in the EU, the government of Spain has launched a "Buy Spanish" campaign. State aid rules that prevent the promotion of national industrial champions are being cheerfully trashed. Despite the deliberately reassuring communiqué that closed this weekend's summit, a genuine assault on the European single market is brewing.

If Europe starts rolling back the four freedoms, the implications will stretch well beyond economics. Protectionism and nationalism are close cousins. The principles of consultation, co-operation and open borders within the EU have helped to repress the old, nationalist demons.

After the end of the cold war, the EU notched up another great achievement – its enlargement to include the countries of the former Soviet bloc. This was a painstaking, serious and generous exercise in spreading political and economic freedom across the Continent. It is hard to remain an unabashed eurosceptic when you see how much EU membership meant to countries such as Poland or Slovakia. Yet the central Europeans are now feeling abandoned and panic-stricken.

Division in Europe would be particularly unfortunate at a time when there is an urgent need for international co-operation on a global scale. The Brussels institutions are adept at finding "cross-border issues" that would justify an expansion in their powers. Quite often their case has been weak. But the international economic crisis and global warming have made their case far more effectively than any EU policy document.

The EU is the best example we have of international governance. If it starts to fall apart under the strain of the crisis, the outlook for solving other difficult global issues will be much darker.

That is not to say that the democratic problems with the Union have gone away. They certainly exist – and they are serious. The drive towards a federal union will doubtless be revived at some point, and should be opposed when it is. But that is not today's problem. The threat over the next year will be the disintegration of the EU.

If you compare Europe with most other bits of the world, it still looks pretty good – prosperous, peaceful, free, a little on the dull side. But part of the EU's problem is that its main achievements do seem technocratic and boring. "Defend the single market" is not the most inspiring of slogans.

But the "four freedoms" represent important rights: the right to live and work anywhere in Europe; the right to make a business deal without the government stopping you; the right to hop on a train to Paris or a plane to Madrid without being hassled at immigration.

In the coming years, the real threat to these freedoms will come from national governments in a panic – not from the dreaded bureaucrats of Brussels. On the contrary, it will be up to an enfeebled European Commission to try to hold the line.

Strangely enough, I now feel a certain protective warmth towards the embattled eurocrats in their Brussels skyscrapers. This would have been hard to imagine when I arrived in the city all those years ago. But it has finally happened. I love Big Brother.