‘A declaration of war’ said the front page of the Guardian. ‘This is like Pearl Harbour’ said many Americans reacting on the street. But this was not war, in a classic sense. It was not Pearl Harbour because the days of attack by foreign powers are over. The real message of the impossible tragedy of 11 September is that we live in an interdependent world where no territory, however rich and powerful, can insulate itself from catastrophe.

It is not the start of a war because there is no one to attack. It could have been Osama Bin Laden or a number of Islamic militant groups. But nobody knows, yet, and maybe we never will know. The only consequence of finding a foreign state to blame, say Afghanistan, would be to worsen the situation. Retribution from the air will kill yet more people and create more alienated youths ready to be suicide bombers.

We live in a world where old-fashioned war between states has become anachronistic. Indeed, this may be the real meaning of globalisation. And this is perhaps why we became conscious of globalisation after the end of the last great global clash, the Cold War. We live in a world, where states no longer exercise the ultimate threat of war as a way of determining international relations. To day, states are still important but they function in a world shaped less by military power than by complex political processes involving international institutions, multi-national corporations, citizens groups, and indeed fundamentalists and terrorists.

The end of old-fashioned war does not mean the end of violence. Instead, we are witnessing the rise of new types of violence, justified in the name of fundamentalism of one variety or another, and perpetrated against civilians. In these ‘new wars’, the aim is no longer military victory. Rather the strategy is to gain political power through sowing fear and hatred, through creating a climate of terror. The new entrepreneurs of violence may have their allies in states but this is not the ‘clash of civilisations’. It is not the civilised world versus the fundamentalist other. In today’s world, the civilised and the uncivilised live side by side, in America as well as Afghanistan, in Israel as well as Palestine, in Belfast as well as London.

These ‘new wars’ have a tendency to spread across borders and over time. They speed through networks of criminals and extremists. They spread through the trauma and insecurity they generate, and they spread through the vested interests of the new entrepreneurs. And these are ‘wars’, that, for all the same reasons are very difficult to end.

This is the kind of violence experienced in the Middle East, Africa, the Balkans, the Basque country and Northern Ireland, and even the inner cities of the United States. But up to now, there has been an illusion that America is, more or less, immune. The United States has been comfortable in the assumption that wars happen somewhere else. It has been able to maintain the myth, so important to the American psyche, that there are still wars on the model of world war two, in which virtuous states win over evil states, and the US can act as leader of the virtuous states at a distance. National missile defence is part of this myth; it would allow the US to bomb evil states at a distance safe in the knowledge that its territory is protected.

The new kinds of war cannot be ended through military means. There are no easy answers, but the only possible approaches are political; to counter the strategy of sowing fear and hatred with a strategy of winning hearts and minds: to reconstruct a global legitimacy as an alternative to fundamentalism and exclusivism. There is nothing much that can be done immediately in reaction to what happened on 11 September. But a recognition that we live in an interdependent world would be a start. The attackers were criminals not military enemies and should be treated like criminals, according to international law, not through the illusion of war. There have to be co-operative efforts to catch them and bring them to justice. And there have to be co-operative efforts to solve deep-rooted problems that give rise to the kind of anger, despair and fanaticism that are used to justify the horrors imposed.

The big danger is that the United States will not get the message. The temptation to mobilise patriotic fervour, to recall the Pearl Harbour spirit, could lead to a war against invented enemies, which would give the entrepreneurs of violence yet more material for the next vicious adventure. Or it could lead to yet more isolationism, pulling up the imaginary walls around the United States, and trying to ignore the conflicts, problems and disasters in the rest of the world that cannot, in practise, be contained beyond walls. Something changed in the world on 11 September. Can we expect another violent century, where the violence is pervasive and continuous, in contrast to the bursts of statist destruction that characterised the twentieth century? For that will be the consequence if the message of these events is not understood. The world is a very dangerous place. The best we can hope for is that a new understanding will emerge from the catastrophe, that the destruction of the World Trade Center will act as a catalyst for a new political project aimed at finding a co-operative global alternative.