Downtown Kabul is Fat City, Afghan style. The first shock for a new visitor is how undamaged and commercially busy it looks. On my second day, I bought a camera, from a large range, from the only Hindu shopkeeper left in town, and French cheese and Carr's water biscuits with sesame seeds from a shop in Flower Street - which had a far more elaborate choice of English biscuits than most of the better US supermarkets.

In the exchange market, huge sums of money change hands every day. Or rather, huge piles. With the Afghani at around 38,000 to the dollar, and the largest note the 10,000 Afghani, you need to bring along a shopping bag if you change $100. There is even a new international hotel, set up by an extremely brave and enterprising returned Afghan emigré from New Jersey. For a variety of reasons, it would be difficult to fit it into the Michelin star system, but it certainly deserves five stars for effort.

Most days, there is a traffic jam on the main roads; and since the Kabul Valley is a depression between mountain ranges, it's not surprising that I detected the beginnings of smog. There are no traffic lights, but white-helmeted traffic policemen do their best at some of the crossroads: given the way Afghans drive, their job probably demands more physical courage than any other in Kabul today. Their colleagues in the Interior and Defence Ministries do not help the situation by cordoning off huge areas of the central city every time a Western official drops by - which in February seemed to be practically every second day. Passage could sometimes be assured with a 50,000 Afghani bribe, however, or by waving a Western passport.

Through the roar of the traffic and the incessant squawking of the horns can be heard the tinny sound of Indian film music: with the Taliban gone, urban Afghans have lost no time in reindulging their old love of Bollywood, and the video and cassette shops are doing a roaring trade. The film industry, too, is pushing out new shoots in the shape of music videos made for leading Afghan singers. One was filmed in London and features a romantic scene outside what appeared to be Willesden Green Tube Station - an impossibly exotic scene for the vast majority of Afghans, just as your average Afghan bazaar is for newly-arrived visitors from London.

In the former upper-class residential area of Wazir Akhbar Khan, the Western embassies lurk behind high walls and rolls of barbed wire, while the NGOs and media organisations have taken over the villas of the former elite. Repeated lootings have emptied the villas of much of their stuff but in every other respect they resemble their equivalents elsewhere in South and Central Asia. Each of these organisations indirectly supports a small village of relatives of their Afghan staff - not to mention the beggars who cluster round their gates. Except among diplomats, attitudes to security are carefree, despite the best efforts of some Western security firms to peddle their services. One reason is the presence of the International Security Assistance Force (ISAF), patrolling in their jeeps and more rarely on foot.

Fat City lasts for between ten and thirty minutes as you drive out of town, depending on the direction and the traffic. Then, long before you reach the border of Kabul's sprawling municipal district, which is the area controlled by the ISAF, the intact houses run out and the great fields of ruins begin, stretching across the plains and climbing up the surrounding foothills. These are the relics of the Mujahedin bombardment of Communist Kabul during and after the Soviet occupation, but more of the years 1992-96, when, after the Communists fell, the Mujahedin groups turned on each other and tore the city and the country to pieces.

And out in the ruins, the heirs of the Mujahedin are waiting: the various militias of the Northern Alliance, which captured Kabul in November after the US Air Force had broken the Taliban lines to the north. There are Hazaras from the mountains of Hazarajat to the west, and Pashtuns from the handful of Pashtun groups which joined the Northern Alliance to go on fighting the Taliban. Most, however, are Tajiks from the Panjshir Valley and surrounding areas: the people of Commander Ahmed Shah Masoud, strongman of the Mujahedin 'Government' in 1992-96, who was assassinated by al-Qaida (or the Taliban) last September.

The commanders of these groups now owe allegiance to the Defence Minister, General Fehim, or the Interior Minister, Yunus Qanuni - both Panjshiri leaders and former aides to Masoud. The portrait of the deceased leader is everywhere in Kabul - or at least, everywhere the Panjshiris control or where people are afraid of the Panjshiris and want to please them, which is to say most places. Behind their hands, Pashtuns and Hazaras growl and sneer. Their memories of the years when Masoud and his men ruled Kabul are not happy ones. This is true even of many Kabuli Tajiks, especially from the shopkeeping class. On the other hand, today the militia with the very worst reputation for criminality in Kabul is ethnic Pashtun - a group belonging to the former Northern Alliance. So it would be wrong to see the divisions of post-Taliban Afghanistan in clear-cut ethnic terms, like those in Yugoslavia - though this could develop, if certain trends continue.

What sort of quarters the different groups live in depends on their power and status, and that of their commanders. Some have occupied intact military bases or private compounds; others live in semi-intact hovels in the ruins. Exploring the ruins near the battered zoo, I encountered a group of Panjshiri fighters under a commander called Abdullah, part of the wider group of General Bismillah Khan, and under the formal authority of Yunus Qanuni - a layered set of allegiances, based partly on ethnicity, partly on clan, partly on personality, but not really on any modern system of hierarchy or discipline.

A much more striking, and explicitly medieval setting for such groups are the old hill forts which rise from the plain across which the city of Kabul now stretches. Like all traditional Afghan architecture, these forts have a timeless feel: a matter both of their design and of the clay from which they're built. Especially when, as so often, they lie in ruins, you can't be sure whether you are looking at Afghanistan in 2002 AD, or Jericho in 2002 BC - except that Jericho was not defended by heavy machine-guns.

Three things emerge from talking to the forts' defenders from the former Northern Alliance, especially the Panjshiris. Two are contradictory. On the one hand, most are determined to hold onto what they have gained by war (and thanks to the US Air Force). am not a politician,' Commander Ishaq, a Shomali Tajik (aligned with the Panjshiris) occupying the fort of Koluleti Poshteh, told me. 'I am a follower of General Fehim . . . and my job is to kill the enemies of Panjshir, whoever they may be. While Karzai and his ministers were hiding safely in America, we fought and died to defeat first the Russians and then the Taliban . . . And if anyone tries to take power from us, I will fight them too, whether it is Americans, Canadians or Africans.'

If the political process initiated by the Bonn Conference is to continue, the Panjshiris - and their analogues in the provinces - must be persuaded, pressured and bribed to give up some of their hold on power. As Ishaq's remarks indicate, this is not going to be easy, though it will be made easier by the second characteristic of the fighters I met - they are very tired of war.

Commander Abdullah has been fighting for twenty years. 'Whatever happens, there will be no more war,' he declares after a litany of complaints about Western dictation, and the return of cowardly, decadent Afghan emigrés from the West to rule over 'the real Muslim Afghans, the real fighters'. 'We are all of us tired of fighting.' Looking at his scarred, deeply lined face, I didn't find this hard to believe - at least of his older men. With the younger ones, it might be a different matter. Some of them look ready for many more years of fighting.

Another very important issue for groups like Abdullah's is that - at least by the time I left at the end of February - none of them had been paid by the new Interim Administration. Most of them have nothing to look forward to in their impoverished rural homes, and are too proud to join the proletariat in the cities. Members of the Government spend most of their time travelling abroad; meanwhile, the city of Kabul gets richer by the day. We know from many parts of Africa where that combination leads: sooner or later, to military mutiny and coups, and to the looting of the cities by a 'soldateska' that may be brutal and licentious, but also has legitimate grounds for resentment.

Sinister legends cluster round some of these commanders, though not all of them are to be believed. I don't, for example, believe the story about wolf-men - humans raised as wolves, like Mowgli - to whom commanders feed recalcitrant prisoners. Apart from anything else, I heard about three separate cases, which would suggest that the remnants of Afghanistan's wolf population have a public outreach programme second only to the Swedish-Afghan Committee. All the same, watching fighters like Commander Ishaq's as they look down into Kabul, you wouldn't need to have smoked too much hashish to imagine that you could see their ears lengthening, their eyes turning yellow, and their tongues beginning to loll.

This is certainly what the women of Kabul feel. Accounts in some of the Western media of women tearing off their burqas in joy at their liberation are grossly exaggerated. During the three weeks I was in Kabul, I saw precisely three women on the street without burqas, and two of those were ancient crones long past worrying about what men might say or do. In many cases, the retention of the burqa is due to a conservatism which predated the Taliban by quite a number of centuries. But educated women with whom I talked in schools and hospitals (unveiled once safely indoors) said that the main reason is fear: partly of a conservative backlash, but mainly of a repeat of the rapes and abductions carried out by the present Northern Alliance forces and their allies when they ruled Kabul in the early 1990s. Many were convinced that had it not been for the presence of ISAF, those days would already have returned; support for an extension of ISAF's presence is overwhelming among the Afghans to whom I spoke, not just in Kabul but in the Pashtun provinces, too.

Mind you, across most of Afghanistan the fighters are behaving pretty well, all things considered. Around Mazar-i-Sharif in the North, there are ethnic clashes and what amounts to ethnic cleansing, and in a couple of Pashtun provinces there are bitter feuds between local warlords, fuelled in part by American subsidies and guns; but this is not characteristic of the country as a whole - at least not yet. Herat and the surrounding areas are kept in order by one relatively benign warlord, Ismail Khan, and his men; the central provinces are controlled by the forces of their Hazara population, which seem to be fairly disciplined.

In the Pashtun provinces which I visited, a working - if fragile - consensus has been achieved by the local commanders, including Hazaras and others as well as Pashtuns. These agreements are then embodied in the decisions of local councils (shuras or jirgas) which play in miniature the same kind of legitimising role which the Loya Jirga, or grand national assembly, is supposed to play in Kabul when - or if - it meets in June.

It's probably an error of the modern mind to think that the existence of a multiplicity of armed groups with different allegiances necessarily and automatically leads to continual warfare. Medieval Europe lived with this situation for several centuries, preserving some kind of basic peace and order for most of the time. It's also the case that an intelligent brigand does not want to plunder commercial activity so heavily that it stops altogether.

This became obvious to me during journeys along two of Afghanistan's great highways: the circular road which links four of the country's five cities, and the road from Kabul through Jalalabad to the Khyber Pass and Pakistan. Admittedly, a strong sense of self-preservation led me to end my journey on the circular road at Ghazni, since between there and Kandahar the danger of attack is very much greater. As far as Ghazni, however, not only did the road seem to be safe enough, but as far as I could see the various checkpoints along the way were only taxing lorries and such cars and buses as were obviously overloaded with goods for trade.

The road itself varies from the atrocious to the non-existent. A few miles from Kabul, the paving ends and from then on, it's no more than a large track. For considerable stretches, it simply merges into the flat land on either side. Grossly overburdened trucks roar across the plain - trucks which carry most of the trade between Northern and Southern Afghanistan, and indeed between Central Asia and Pakistan. Many are painted in the South Asian fashion, with brightly-coloured wooden carvings over-hanging the cabs. They're reminiscent of the ceremonial howdahs of elephants, especially when clusters of people as well as enormous bundles of goods are perched on top. But as these fantastic conveyances lurched into sight through gusts of rain and snow on the road to Ghazni, what they really brought to mind were galleons manoeuvering for position in a stormy sea of mud. Just repairing these unfortunate vehicles after every gruelling stage provides work for hordes of mechanics in every bazaar along the way.

The scenery along the road to Ghazni is pretty gloomy, especially in winter. A wide valley of yellow-brown earth extends between ranges of black and grey mountains. I crossed those ranges with the Mujahedin in the winter of 1988-89, and understood for the first time why our down-to-earth pre-Romantic ancestors so loathed and despised mountains.

But for Romantic prospects, the road from Kabul to Jalalabad takes the prize. This is the classic Afghanistan of the British Imperial imagination - the scene of several British campaigns and one signal catastrophe. As the road plunges through the deep gorges, with the Kabul River roaring and gurgling to the side, the mountains tower above, shimmering golden and white in the sun, drifting in and out of the clouds like spectres. Then as you descend into the great valley of Nangarhar, the change in the landscape hits you with a near-sensual impact. Beginning with a faint skein of trees along the river, the shades of green spread and deepen until the whole landscape seems to glow against the fantastic painted background of mountains and sky.

After weeks on the high plains, the valley of Nangarhar seems close to the Islamic vision of paradise; indeed, Jalalabad was the unofficial second capital of the old monarchy, and the site of its winter palace. As with the old summer palace at Paghman near Kabul, the ruins of this edifice can still be seen. The difference is that while Paghman was mostly destroyed in fighting, the palace in Jalalabad was deliberately burnt down a few years ago on the orders of local radical mullahs - an act of wanton vandalism. The reason given was that members of the royal family had entertained their mistresses there, and held 'orgies' - in other words, entertainments featuring dancing girls, which used to be popular among the Afghan upper classes. This addition to Nangarhar's extensive collection of ancient and modern ruins was the work not of the Taliban, but of Jalalabad's present rulers from the former Mujahedin, during their previous period of rule over the region.

The experiences of the Mujahedin since 1996, when they were driven out by the Taliban to the general applause of the harassed and infuriated population - have had a chastening effect, or so local people say. The old swagger is greatly diminished. A shopkeeper gave me an example of the difference. He said that, of course, the fighters from the various groups never pay for what they take from his shop. But today, a fighter will come and take one packet of cigarettes for himself and his comrades: back in 1992-96, he would have brought a bag, and swept the whole shelf of cigarettes into it. The commanders seem to be aware of how their men disgraced themselves in the eyes of the population - and for the moment at least they are keeping them well in hand, if only because they want to get their men into the Loya Jirga. For this to happen, good relations with the local population are required.

Beyond Jalalabad, the road to the Khyber runs between many old battlefields, and two more recent ones. A few minutes drive to the east is where the battle of spring 1989 took place, when Afghan Mujahedin and radical Arab forces, backed by the US and Pakistan, tried to capture the city from the Communists after the Soviet withdrawal. Further on, the mountains of Tora Bora rise to the south of the road - the site this winter of a massive US attempt to destroy those same Arabs and their allies.

Nearby lies the Hesar Shahi refugee camp, funded and administered by a Saudi-based Islamic relief organisation. It's full of refugees from various waves of fighting who for whatever reason have not been able to make it out to Pakistan. Some of the people live in proper military-style tents, but others are in miserable shelters patched together out of cardboard, plastic sheeting and what look like old clothes.

Ten years ago, such camps in Pakistan, funded and influenced by Arab organisations, gave birth to the Taliban. Today, the US is rightly concerned that certain Islamic charities, especially from Saudi Arabia, are funding terrorist groups, and is trying to shut them down. It would be reassuring in this context to think that even a fraction of the money the US spent on subsidising Arab radicals in the 1980s, and bombarding them today, had been or will be spent on helping the refugee camp a few miles to the north of the Tora Bora battlefield; but of this there is as yet little sign. And if Hesar Shahi is still there twenty years from now, we'll have no right to complain if Afghan-based Islamist extremism is there too.

But then who is thinking of Afghanistan decades from now? The current war is far from over, yet the Bush Administration's attention has already passed to its plans for a war in Iraq. We have heard repeated assurances that the US will not repeat its mistake of the early 1990s and once more forget about Afghanistan. How pleasant it would be to have confidence in that promise.

Originally published in the London Review of Books, Vol. 24, No 7, April 2002