

The unipolar moment of American supremacy has passed. But the new multipolarity may prove to be very nasty indeed
Welcome to the world's new multipolar disorder. The state of Israel is now at war with Hizbullah, but not with the state of Lebanon. The Lebanese state does not control its own territory. Iran heavily influences, but does not control, Hizbullah. Fresh from its triumph at the G8 summit in St Petersburg, Russia probably has the closest relations of any of the G8 powers with Syria (to which it supplies weapons) and Iran. China is in there too, as are the leading European powers - once again failing to act as one European union. The US possesses the mightiest military the world has ever seen, and how is it being used? To evacuate its citizens from Lebanon. If the US secretary of state, Condoleezza Rice, manages to broker an end to the fighting, it will only be through complex multilateral diplomacy.

So, welcome to the new multipolar disorder - and farewell to the unipolar moment of apparently unchallengeable American supremacy. The hyperpower! The mega-Rome! Remember that? Moment turns out to have been the right word: a brief episode between the end of the old bipolar world of the cold war and the beginning of the new multipolar world of the 21st century. This new multipolarity is the result of at least three trends. The first, and most familiar, is the rise or revival of other states - China, India, Brazil, Russia as comeback kid - whose power resources compete with those of the established powers of the west. The second is the growing power of non-state actors. These are of widely differing kinds. They range from movements like Hamas, Hizbullah and al-Qaida, to non-governmental organisations like Greenpeace, from big energy corporations and drug companies to regions and religions.

A third trend involves changes in the very currency of power. Developments in technologies with violent potential mean that very small groups of people can challenge powerful established states, whether by piloting an aeroplane into the World Trade Centre in New York, targeting a missile at Haifa, taking on the US military in Iraq, bombing the London underground, or squirting sarin gas into the Tokyo subway. Developments in information technology and globalised media mean that the most powerful military in the history of the world can lose a war, not on the battlefield of dust and blood, but on the battlefield of world opinion. If you look at the precipitate decline in US popularity since 2002, charted by the Pew Global Attitudes polls even in countries traditionally sympathetic to Washington, you could argue that this is what has been happening to the US.

The net effect of these very disparate trends is to reduce the relative power of established western states, above all of the US. Little remarked by much of the world, and obscured by the continued warlike rhetoric that I wrote about two weeks ago, the Bush administration has in fact adjusted to this reality in the president's second term. Since 2005, in an approach crafted by Rice, it has tackled not just the two other members of the "axis of evil", Iran and North Korea, but also most other challenges, through multilateral diplomacy - though always insisting that the option of using force remains on the table.

This approach has been handicapped by the massive concentration of time and resources on Iraq, and by a reluctance to engage in direct, bilateral negotiations with nasty regimes such as Iran, but the American foreign policy of 2006 is certainly very different from that of 2003, as the Iraq war was launched. North Korea test-fires missiles capable of carrying the nuclear warheads that it's already making? Washington says: come back to the six-party talks! Iran resumes uranium enrichment? Washington says: we're going to take you to the UN! Hizbullah launches missiles at Israel? Washington says: the hour of diplomacy has come!

When Jacques Chirac spoke fondly of multipolarity, back in 2003, he conflated two claims: the world is multipolar, and that's a good thing. Claim 1 is being proved right. Claim 2 has yet to be confirmed. For a start, it matters a lot whether this is multipolar order or multipolar disorder. Order is a high value in international relations. It stops a lot of people being killed. At the moment, we have multipolar disorder, and it's not clear what the shape of a new multipolar order might be. Historically, the emergence of new powers, elbowing for position, has increased the chances of violence. So has contested authority within the frontiers of states.

We liberal internationalists dream of a world of democratic, peace-loving, human-rights-respecting states, working through international alliances and organisations within a framework of international law. Think 192 times Canada. Some of the growing powers fit that vision: Canada and Australia, for example, whose natural resources will make them more important in future; but also, to a large extent, India and Brazil. China and Russia definitely do not, nor do many of the non-state actors that are currently making the running in world politics. Henry Kissinger has suggested that the geopolitics of Asia in the 21st century could resemble those of Europe in the 19th century, with great powers jockeying for position, using war as the continuation of politics by other means. But it could be worse. It could be that kind of great-power rivalry on a world scale, plus terrorists. And corporations. And transnational religious communities. And international NGOs. No moral equivalence is suggested between these very different kinds of actor, but what they all have in common is that they don't fit neatly into a world order of states.

What we are witnessing across the frontier between Israel and Lebanon could be just a prelude. When Tony Blair is long gone, and the American-British presence in Iraq is reduced to a mere token, we may be reminded of Blair's earlier warnings - so unhappily hitched to the Iraq war - about the danger of the coming together of weapons of mass destruction, terrorism and failed states. Nuclear proliferation - the proliferation of WMDs altogether - is one of the greatest dangers of our time. It's right up there alongside global warming, and as difficult to address. It seems to me a sustainable claim that the danger of nuclear warfare is now greater than at any time since the Cuban missile crisis of 1962, though the scale of a likely conflagration is much smaller. Who would be prepared to risk a bet that we won't see a nuclear weapon fired in anger over the next 10 years? I wouldn't. Would you?

So be careful what you wish for. In principle, multipolarity is an advance on unipolarity for the same reason that it is wise to have a well-ordered division of powers inside a democracy. But it's an advance only if it comes as a version of liberal order - with the adjective and noun being of equal importance. If, however, this week's events are a foretaste of things to come, the world's new multipolar disorder could be very nasty indeed. And then you might even find yourself nostalgic for the bad old days of American supremacy.

· www.timothygartonash.com