Europe's next chapter starts now. It rests on looking beyond our borders

Timothy Garton Ash

Well, they did it beautifully. Despite the rain, I found the official celebration of the fall of the wall in Berlin night a genuinely, even an unexpectedly moving affair. The organisers, presumably guided by Angela Merkel, got almost every accent right. Freedom, Europe and the wider world were the main themes, not German unity. The east German woman from Leipzig who had been locked up by the Stasi for carrying a banner demanding "an open country with free people"; Lech Walesa and Poland's pioneering Solidarity; the Hungarians; Mikhail Gorbachev; the United States. Everyone was given their share of the credit. Oddly enough, the one person who did not receive adequate acknowledgement was Merkel's predecessor, Helmut Kohl.

The toppling of those giant dominoes was a brilliant coup de theatre, partly because you kept thinking: what if it goes wrong? What if one of the dominoes topples sideways, or just stops? But the Germans got the engineering right, of course – as efficient in toppling dominoes as in making BMWs. And how good to put near the end of the celebration an interview with Muhammad Yunus, the Bangladeshi pioneer of microcredits, who talked about the wall still separating rich north from poor south: die Mauer der Armut, the poverty wall.

So, three cheers for Germany and three cheers for Europe. Looking at the searchlights piercing the night sky above the Brandenburg Gate, we could reflect on the extraordinary distance travelled in a city that was at the heart of two world wars and the cold war. After all, for at least 50 years, from 1939 to 1989, searchlights at the Brandenburg Gate had been a prelude to killing people, one way or another, rather than a signal of their peaceful liberation.

But then it was over. Berliners trudged back through the drizzle; the police started clearing away the crowd-control barriers; and already at dinner, we are told, the leaders of the EU were quietly conspiring in corners about who should be the next so-called president (that is, chair) of the European council, and the new high representative for foreign and security policy. Perhaps that was what Gordon Brown, Nicolas Sarkozy and Merkel were really thinking about, on their chilly podium, as the long ceremony ended with young people from all over the world joining in the distinctly Obamaesque refrain of a specially written song, "We can be as one". (As for Silvio Berlusconi, he seemed to have his eyes closed whenever the television camera caught him. Dreaming of …? Better not ask.)

Should the president of the European council be the inspiring, haiku-writing Belgian, Herman van Rompuy? Should the high representitive be Britain's brainy foreign secretary, David Miliband? Has Miliband genuinely ruled himself out, bravely choosing to remain on the bridge of the New Labour Titanic? Will Peter Mandelson nobly step into the breach – then becoming, presumably, the Lord High Representative? (Cue music by Gilbert and Sullivan.) Or will the job go to former Italian prime minister Massimo d'Alema?

I have already proposed my candidates: the Nobel peace prizewinner and elder statesman Martti Ahtisaari for the chair; Joschka Fischer or, failing that, Miliband for high representitive. These personalities matter. Yet even if the usual EU haggling behind closed doors ends up producing two weak, colourless figures – two rabbits out of a grey hat – we will still have the possibility of creating a Europe that acts more "as one", to recall the words of the Berlin song. We will still be able to create the institutions, notably a new European foreign service. And what we do with those institutions anyway depends, with the Lisbon treaty as without it, on the political will of member states and their democratically elected governments. If they want it to happen, it will. If they don't, it won't.

They should want it to happen, because whether we in Europe have anything much to celebrate in another 20 years' time will depend on whether we get our act together in our relations with the rest of the world. Of course, there are still vital things to be done inside the frontiers of today's EU: the creation of new jobs, the integration of Muslim fellow citizens, to name but two. But increasingly the key challenges for the European Union lie not within its own borders but beyond them.

Geographically, the agenda starts with the rest of Europe that is not yet in the EU. Enlargement fatigue is palpable at every turn, but there is still a lot of Europe to be brought in, before "Europe" is really Europe: the rest of the Balkans, Ukraine, Moldova, Belarus, perhaps Georgia and Armenia – and, as a strategically vital special case, Turkey. Provided they meet all the conditions for membership, we should want all these countries to be EU members, in our own, long-term, enlightened self-interest, as well as in theirs.

Then there is Russia. If the EU does not have a Russia policy, it will not have a foreign policy. And to have a common Russia policy, it needs a common energy policy. To the south and southeast, there is the question of how we help the modernisation, liberalisation and eventual democratisation of mainly Muslim countries which are not, in any foreseeable future, going to be members of the EU. Though the Berlin wall has gone, there is still the wall separating Israelis and Palestinians.

Further afield, there are the great emerging powers such as China, India and Brazil. Measured against its own unhappy divided past, Europe has ascended; in relative power, it is descending. The United States no longer looks automatically to Europe as a strategic partner. (Obama's appearance in a video message at the Brandenburg Gate only served to remind everyone of his physical absence. They should have left it to Hillary Clinton.) Miliband's argument that we face the choice between a G2 world, with the crucial shots being called by the US and China, and a G3 world, including the EU as the third partner, usefully simplifies and exaggerates to make the right point.

Beyond that, looming larger still, is the poverty wall of which Yunus spoke. The EU has the largest economy in the world. It and its member states combined give more than half of the world's official development aid. If it acted "as one", and strategically, no one would have a better chance of lowering the wall between the rich north and the poor south. Largest and most important of all is the planetary challenge of climate change, with time now running out before the Copenhagen summit in early December.

The point is this: you don't need to have any sentimental attachment to Europe whatsoever to understand that to tackle these problems we need the scale and clout that only Europe gives. This has nothing at all do with dreams of an "ever closer union". Europe here is a means, not an end in itself. The purpose is to defend and advance the vital interests of all our citizens, Brits included.

Europe has a great story to tell from the last 60 years, and it was told brilliantly in Berlin on Monday night. But that story is mainly about what we have achieved inside Europe. The next chapter will depend on what we do outside it.