Johann Hari

This week, a summit will take place in Berlin that not so long ago would have looked like a piece of utopian sci fi. The leaders of a unified Europe - free, democratic and at peace, from the shores of the Atlantic to the Ural mountains - will gather to celebrate the 50th birthday of the European Union. They will truck and barter over a hundred issues, but it would not occur to them to pick up arms against each other, and it never will again.

There's so much poison pumped into the British psyche about the EU that it's worth stopping for a second to realise how incredible this is. When my grandparents were born, the face of Europe was scarred with mud-trenches where one group of gangreous young European men massacred and gassed another group of gangreous young European men in a meaningless parade of nationalism. When my parents were born, Europe was a rubble-strewn wreck recovering from a genocide and the death of more than 40 million fighters. The historian Mark Mazower wrote a book called 'The Dark Continent' - and he meant us.

So wipe the angry flecks of Euroscepticism off the pictures you'll see from Berlin and celebrate. Whatever happens in Europe in the next fifty years, it will not be war - and that is, to a significant degree, thanks to the EU. But it is not enough to build the Union on a negative. We have to ask: what is the EU for now? Some honourable supporters of the Union believe there is no need to offer a new agenda. They argue that - to borrow a phrase form the Northern Ireland peace process - there should be "strategic ambiguity" about the EU's role, so each member can project onto the Union whatever they want to see. I don't agree. The rejection of the European Constitution by a string of European electorates in 2005, and the ongoing dire poll ratings of the EU, shows that if the Union doesn't have a clear purpose, it will sag and sunder. If it is going to last, the EU has to be able to say to its citizens: this is what we do for you.

Flourishing across Europe, it's possible to glimpse three missions on which the Europe's next fifty years - and a shared sense of purpose - can be built.

Mission One: Beating global warming. Only Europe is taking this, the greatest threat to the future of the human species, seriously. The commitment last week to ensure the EU derives 20 percent of its energy from renewable sources by 2020 is on this issue the boldest move by any government, anywhere. It will have a marked physical effect on the planet, but more importantly, it will strip other CO2-pumpers of excuses. We know we will only deal with this catastrophe if we all act together. Europe is showing the world how.

Mission Two: Saving social democracy. Since the 1980s, the US government has been promoting an economic model that funds and fosters corporations and the rich, but largely leaves the middle class and the poor to fend for themselves. Europe believes in a very different model. We know that markets are an essential tool for generating wealth, but we also know that the state must act to compensate for the failings and toxic side-effects of the market. Although there are certainly examples - like France - where this can go wrong, it can also work brilliantly. The Swedes do everything the Americans say you shouldn't: they have a 55 percent top rate of tax, more than a year of paid parental leave, a very high minimum wage, and more. The result? They have 6 percent unemployment, negligible crime rates, and the highest quality of life and the best social mobility in the world. Europe should stand for preserving and spreading this model.

Mission Three: A different kind of foreign policy. If you compare how the US and Europe have dealt with their immediate neighbours, you discover two different ways of approaching the world. The US has attacked Colombia, sprayed it from the air with poisons, and funded one side in a civil war - and the country is a mess. By contrast, Europe has coaxed and cajoled Turkey, holding out the prospect of EU membership on the condition that Turkey becomes more democratic and free. The result is that Turkey is now the most liberal majority-Muslim country in the world. The Europhile writer Mark Leonard calls this "the power of passive aggression". Where the US too often impatiently bludgeons the world while waving the flag, Europe should stand for a softer, smarter post-nationalist approach. Yes, there are instances in which Europe should have been tougher - like the disgraceful failure to act in the Balkans - but Europe's Venusian disposition is something to be proud of.

Of course, we mustn't be unrealistically unbeat; I'm not opening a new branch of Europol called Europollyanna here. To achieve these missions, Europe will have to overcome a slew of serious challenges, from stopping the increasingly dictatorial Vladimir Putin from buying up all our gas supplies, to finding a much better way to integrate the immigrants who are necessary to keep our social democracy afloat.

The most urgent challenge is to dismantle the Common Agricultural Policy (CAP). Does anyone think it is sensible that in 2007, more than half of the EU's budget is spent on agriculture, when fewer than 3 percent of EU citizens rank it as one of their top priorities? This policy is one of the biggest factors in the starvation of Africa, smothering Africa's agricultural industries in their cot by making it impossible for poor farmers to sell competitively in the most enticing markets. For every one euro we give to Africa, the EU takes away seven euros in thwarted trade.

To end this kind of dysfunction, the EU has to make an institutional shift from being a top-down, people-fearing monolith to being a more responsive, democratic body with clear purposes. Ah, sceptics might ask, but responsive to what? At the moment, the EU largely holds the ring between competing national interests. A shared European consciousness is only slender and confined to elites. Yet it is worth bearing in mind how recently other identities we now take forgranted were invented. According to the historian Dennis Mack Smith, in 1871 - the year Italy was fully unified - only 5 percent of its citizens had heard the word "Italy".

The first Italian Prime Minister, Massimo D'Azeglio, said, "We have made Italy, now we must make Italians." The EU has made Europe, now it must make Europeans. We can only do this with clear misisons that mark us out from the rest of the world. So when our leaders gather in the once-broken, now-brilliant city of Berlin, they should not only mark the past fifty years of peace. They should launch new missions that can make the next fifty years a period of real, lasting European unity this time.

POSTSCRIPT: You can e-mail comments on this article for publication in the Independent to letters@independent.co.uk or just for me to johann@johannhari.com

There's a critical response to this article at http://ewanwatt.blogspot.com/2007/03/europe-europa.html