Jack Straw: In this new world, all of us must rethink our attitudes to sovereignty

'Pooling our sovereignty in the EU is important as it strengthens our ability to meet shared challenges'

Europe, that perennial mainstay of our national political debate, has fallen from view following the events of recent weeks. Arguments about sovereignty might seem trivial at a time when all nations have been facing a common danger. In fact, the debate about sovereignty is more important than ever.

We cannot afford to ignore the paramount lesson of the past few weeks since those terrible events of 11 September: nations are stronger when working together than they could be alone. Closer co-operation with our friends and closest neighbours in Europe is an essential safeguard as much for our security as our prosperity.

Individual European countries, Britain included, were among the first to rally around the United States in its hour of need after 11 September. The natural alliance between the countries of North America and Europe has been at the core of the international coalition against terrorism in all of its aspects – military, diplomatic and humanitarian.

Acting collectively in the European Union, we have risen to the challenge with plans for a common European arrest warrant, a common definition of terrorism, measures to freeze the assets of suspected terrorists, recognise each other's court orders and share intelligence.

These are all vital steps for our security which could not have been taken either quickly or effectively without the intergovernmental co-operation which is now a familiar feature of the workings of the EU.

But quite apart from the many practical benefits which we derive from our membership of the EU, there is a wider point to be made here. The events of 11 September brought home to us all, in the most brutal way possible, that isolationism does not and cannot work. We cannot afford to ignore events anywhere in the world.

The world's neglect allowed Afghanistan to become a haven for terrorists – with devastating consequences. When events in the most remote and alienated place on Earth can have such an immediate impact on the richest and most cosmopolitan city in the world, what does this mean for nation states?

Nation states are and will remain the foundation of the international order. The global system is founded on states – and one of the greatest threats to global security comes when states, like Afghanistan, collapse into chaos.

But in a world where states and the interests of their citizens are so obviously interdependent, we need to re-think our attitudes to concepts like "independence" and "sovereignty".

The truth is that "sovereignty" has never been absolute. Is the epitome of sovereignty a hypothetical island people, wholly isolated from any contact with the rest of the world? No. For them, sovereignty would be irrelevant. Sovereignty has always been a relative concept – since it defines the position of a nation in relation to other nations and peoples.

Exactly what comes with that sovereignty in practice depends on many other factors. In today's world, by sharing sovereignty, a people may end up with more, not less, independence of action, more, not less, internal self-government and more, not less, control over their lives.

This is because our security depends on the influence we can exert over events in the rest of the world, not our ability to stop our friends from influencing us.

Does anyone really imagine that, in the past few crucial weeks, Britain's influence in Washington would have been anything like as strong if we were not also a strong voice in the EU? Of course not. In the modern world, our strength as an independent nation derives from the strength of the alliances and partnerships we make with others. Indeed, this is a lesson which we learned long before we joined the European Union.

For more than 50 years, we have been a full and enthusiastic member of other treaty-based organisations such as Nato, which pools responsibility over our national defence – an area which goes right to the heart of our national sovereignty. We pool sovereignty in the United Nations, where Security Council resolutions have the force of international law.

Pooling our sovereignty in the EU is still more important, as it strengthens our ability to meet so many other shared challenges which have a real and daily impact on our national life. Being part of the EU does not mean that 14 other countries automatically fall into line behind the British view. Of course we have to negotiate, and sometimes we have to compromise. But there can be no doubt that in one area after another – trade and jobs, financial services, a cleaner environment – the EU gives us much greater strength to look after the interests of the British people.

No one suggests the Italians are any less Italian because they are part of the EU. Yet Europe retains its capacity to excite fears about what it means to be British.

We have to challenge the false notion that we cannot be British and European at the same time. As Linda Colley points out in her book Britons: "Identities are not like hats. Human beings can and do put on several at a time." Europe simply provides a further layer of identity. It need not challenge or subvert the other loyalties which exist. We are a European nation, and always have been. We are European today in the places we trade with, the places we go on holiday, the food we buy in the supermarkets, the cars we drive to work in. Europe is part of what we are.

The EU does not threaten our independence, our sovereignty or our identity. Rather, in today's world, more interdependent than it ever has been, the EU provides the surest guarantee that our voice will be heard in the world.

Tomorrow, in a speech in Birmingham, the Prime Minister will be making the case once again for strengthening our sovereignty by pooling it, where we choose to, with our friends in the European Union. Three weeks later, the summit of European leaders at Laeken will begin the task of reforming the European Union for the longer term.

Our objective will be to build our kind of Europe: an EU which is better understood, better liked and with which our citizens are familiar and comfortable; an EU which concentrates on the radical reform and renewal which a rapidly changing world demands. The best way to build our kind of Europe, and to strengthen our sovereignty at the same time, is not to isolate ourselves on the fringe, but to win friends and win arguments.

The author is Foreign Secretary