Lawrence Freedman: This is the Third World War – and the stakes are high

'Like the First and Second World Wars, the core confrontation is a vortex pulling other conflicts in'

Was 11 September 2001 the start of the Third World War? To save the suspense, the answer is "yes", but only with an updated concept of the Third World War. The old concept was of an exaggerated, more dangerous version of the First and Second World Wars: a cosmic struggle between great powers disposing of unlimited destructive capacity.

It was nurtured during the decades of the Cold War, with expectations about what would happen should it turn hot shaped by the Second World War's finale, the atom bombings of Hiroshima and Nagasaki. In the event, the prospect of an even more horrendous conflagration encouraged the superpowers to be cautious. The Cold War came to an end peacefully, as Russia gave up its ideology and the rickety empire which had been constructed in communism's name.

In one critical respect the basis for the Third World War as traditionally conceived has not gone away. The major powers all possess substantial nuclear arsenals, and if events got out of control and just a fraction of the available weaponry was unleashed, the ultimate catastrophe could still be upon us.

The continuing power of this imagery has been evident over the past weeks, whether in the revelation that the planned attack on the US was referred to as "Hiroshima" within the al-Qa'ida network, or in the dust cloud above Manhattan and the designation of the World Trade Centre site as "ground zero", a term first used in the 1950s by those measuring effects of nuclear explosions. The anthrax scare adds to the apocalyptic feel of the moment.

The idea that terrorists might take up weapons of mass destruction and create their own mini versions of the Third World War has been a theme of numerous think-tank studies and official reports. None that I have found addressed the specific option of turning commercial airliners into guided missiles, and most suggested that there were inherent limits on the destructiveness of the terrorists' traditional bombs, almost obliging them to resort to chemical or biological weapons.

Yet the main conclusion of the anthrax attacks, as with the Scud missile attacks on Saudi Arabia and Israel in the Gulf War, is that there are also formidable limits on the physical impact of these weapons, although the psychological effects can be substantial. Whatever is going on with bio-terrorism now, this is hardly mass destruction.

The striking feature of the current contest is the contrast between the high-technology war that America and its allies wage and the stunningly low technology of its opponents. The airliners were hijacked with the most ancient of weapons, the knife, and anthrax has been delivered using the mail.

Allied forces in Afghanistan will be taking on an enemy that could well be at its most exasperating when hiding in caves and setting traps from behind mountain rocks. This is hardly the sort of contest that was ever conjured up by talk of a Third World War. Indeed Pentagon planners have sought to avoid this sort of fighting, because the enemy tends to be so shadowy and tricky, and because they assumed such dirty but protracted conflicts only had the most parochial significance.

Yet this is a war, with vital interests at stake, being fought on a global scale. It is a world war because of the striking geographical spread of the casualties of 11 September; because members of the al-Qa'ida network have either planned or mounted operations in Asia, Africa, the Middle East and Europe as well as North America; and also because of the impact of the clash at its core on a range of regional struggles.

As with the First and Second World Wars, the core confrontation has become a vortex which draws in other conflicts and, in the process, transforms their character. In fact, the secondary consequences of the first two world wars have set the terms for the third.

At one level this produces an optimistic conclusion. The founding aspiration of the United Nations in 1945, to bring an end to destructive great power wars, is at least closer to being realised. The five permanent members of the Security Council are working together in a grand coalition, with America, Britain and France still the leading status quo powers as they were during the First and Second World Wars.

At another level, however, the position is worse. All the current tension points can be traced to the botched nation-building and rivalries that followed past wars. The chaotic ends to the Austro-Hungarian and Ottoman empires after the First World War can still be felt in the Balkans and the Gulf. Colin Powell is having to grapple with Kashmir and the Arab-Israeli dispute, two messes Britain left behind in its retreat from empire after the Second World War. Tony Blair has acknowledged Western responsibility for failing to pay attention to Afghanistan after Russian troops departed at the end of the Cold War.

All these conflicts involve Muslim people, and in all of them, Osama bin Laden has been on the side of those seeking to aggravate. This is not so much a war against terrorism as against a radical political force that seeks to use terroristic methods to coerce Western countries into staying clear of these conflicts as they are brought to a head – and to impose on the Islamic world misogynist theocracies. That is why the stakes are so high.

The easiest part of the Third World War may be in disrupting the operations of al-Qa'ida and driving it and the Taliban out of their bases. The hardest part will be in getting a grip, once and for all, of the vicious legacies of the First and Second World Wars.

The writer is professor of war studies at King's College, London