Europe's raison d'être was clear from the beginning. It was not the common market. It was not created by foreigners for the sole purpose of eroding the sovereignty of the UK, or any other country.
No. Its fundamental raison d'être was a noble one, and Robert Schuman, in his declaration of May 9 1950, made sure everyone knew it: "World peace cannot be safeguarded without the making of creative efforts proportionate to the dangers which threaten it."
Schuman said that pooling the production of coal and steel - the raw materials of war - under one authority, "will make it plain that any war between France and Germany becomes not merely unthinkable, but materially impossible".
Today, the success of this strategy is self-evident. War between France and Germany has become unimaginable, and thanks to successive enlargements we have spread peace, stability and prosperity across the European continent. But 60 years of peace has meant that the image of Europe as a bastion against war is losing its resonance.
Europe's political landscape is today characterised by a tension between those who fear the future, who fear the world, and want protection from it, and those who reach out to it. Should we close or open our doors to what comes from outside? My answer is we must have a Europe which is open to the rest of the world.
But the EU needs a new core purpose. One which looks forward, recognises new realities, that draws inspiration from, but does not depend upon, the achievements of the past. Our purpose is staring us in the face. In 1950 the challenge was securing a lasting peace. Today it is climate change, growing competition from China and India. Mass migration. International terrorism. These challenges are shared by all Europeans, from London to Lisbon. They are challenges which no nation state can tackle successfully alone.
The fact is, the EU is a uniquely effective instrument for helping the UK and other European countries to develop solutions to these new, cross-border challenges. And surely this is the EU's raison d'être for the 21st century: to help Europeans prosper in a globalised world.
There are those who claim that in our interconnected age it is grassroots politics that matters, that globalisation has liberated the local and that the EU is rendered irrelevant in this globalised world. They are wrong. The opposite is true. Globalisation makes the case for the EU.
Size matters in the globalised world. The actors of globalisation, the US, China, India, dwarf any single member of the EU. But the EU has size; 500 million people, the biggest single market and the biggest aid donor in the world.
Yes, countries like the UK have special relationships with India or China, and it is to the EU's benefit that they do. One of the reasons that those countries want good relations with the UK is because it has influence in the EU.
Globalisation has reduced the ability of the nation state alone to provide solutions, while failing to provide a realistic alternative at the global level. Europe - with its shared values and diversity of expertise - fills that gap.
It is to the nation state that most Europeans feel greatest allegiance. But in an era when the challenges facing nation states are global, governments can best deliver for their citizens by leveraging our common strength as Europe.
Europe's agenda is not some alien construction; it is one which responds to the challenges being addressed by the UK and by others in Europe. If the UK wants to tackle climate change, fight poverty in Africa, deliver greater security, if it wants a more open, competitive environment, then the UK needs the EU. But there is another important truth: the EU needs the UK.
Britain is a lead player in Europe. On climate change, for example, the UK's support was vital for putting the emissions trading scheme in place. On security and defence, the UK was last year the biggest contributor of troops to European security and defence policy operations. The next head of the EU's military staff will be British. On Africa, Prime Minister Blair has shown a clear commitment, making it a priority of the British presidency of the EU and the G8.
Finally, on open economies and competitiveness, the UK was a driving force for the creation of the single market and has been a leader in pushing for open trade. The world has changed. Europe has changed too. And the UK now finds itself at the centre of efforts to build a successful, open and global Europe.
And yet it sometimes seems reluctant to take pride in its contribution. The UK will always have influence in Europe. Its size, its economic power and its international networks will ensure that. So the question is: does the UK want to shape a positive agenda which reflects its own agenda, or be dragged along as a reluctant partner? Margaret Thatcher accepted, in the Single European Act, the need for effective institutions to drive an ambitious policy agenda. What was true then remains true now. Europe cannot fight climate change, poverty, threats to security, without effective institutions. If you want these ends, you must have the means to deliver them.
Becoming an effective, global Europe requires improving Europe's capacity to act. That is why institutional reform is necessary. The constitution would have helped. But what Europe needs is a capacity to act.
There is a lot we can do. I do not subscribe to the view that Europe is stuck. But the current set-up is less than optimal: the Nice treaty obliges us to revise the composition of the commission as soon as there are 27 member states. We need reform to improve the efficiency of decision-making. As the number of member states rises, the time it takes to reach a decision increases. This has to change. There is no point reaching the right policies on globalisation if they arrive five years too late.
The distance is growing between Europe and its citizens. Injecting greater accountability into Europe's institutions will help to close that gap. That means developing a more political way of building Europe, rather than a diplomatic, bureaucratic or technocratic one.
There can be no global Europe without greater external coherence. There is no single number for the US to call. The EU is not a federal state. But a European foreign minister, simultaneously responsible to the member states and a vice-president of the commission, would help achieve that coherence.
We also need reform to enable enlargement to continue. Europe's new vocation is to be open, global and engaged. If there was ever a case to argue that the agendas of the UK and the EU were in conflict that is now absurd. And let us also get off the old sovereignty debate. I like Harold Macmillan's answer to that. He said, in 1962: "Accession ... would not involve a one-sided surrender of sovereignty on our part but a pooling of sovereignty by all concerned ... In renouncing some of our sovereignty we would receive in return a share of the sovereignty renounced by other members."
No one is forced to love Europe. What I ask is that the UK demands more from Europe, and keeps giving more in return. It is no longer a question of whether people are for or against. The question is: do you want to make the European Union work.
Jose Manuel Barroso, president of the European Commission; this is an edited extract from the Hugo Young Lecture, given in London on Monday.