Afghan President Hamid Karzai has begun his second term with a pledge to end the fighting there but as Hugh Sykes reports the Pakistan connection makes this a deeply complex problem.
The Taliban came to prominence in Afghanistan in the autumn of 1994
"Fantastic, thrilling, unbelievable," says the blurb on the back cover of the airport thriller Unholy Madness.
The plot is a bit far-fetched. There is this force of Islamic fundamentalist fighters called the Taliban.
They have two branches - one in Pakistan, the other in Afghanistan.
The Pakistan Army is trying to defeat the local Taliban, who have been killing hundreds of people in Pakistani cities with suicide bombers and assaults by armed insurgents.
The Americans and the British have weighed in to help the fight against the Pakistan Taliban.
Meanwhile across the border to the west, the Afghan Taliban are killing American and British troops and they are supplied with weapons, vehicles and mobile phones from across the border in Pakistan, where the Afghan Taliban leadership is based.
So the Americans and the British are supporting a country, Pakistan, which has elements who are supporting the movement that is killing British and American troops.
You could not make it up.
And all I actually made up was the title, Unholy Madness.
The Afghan Taliban leadership are in Pakistan. Pakistan has failed to act against them. And they do kill British and American troops.
And the US Secretary of State Hillary Clinton says the US is standing shoulder-to-shoulder with Pakistan.
From the point of view of an American or British soldier, though, that is pretty much the same as saying that the US is standing shoulder-to-shoulder with the country that is supporting the enemy that is killing them.
This strange, convoluted scenario comes sharply into focus if you look at a map.
The main fighting areas in Afghanistan are in the south - near and around the city of Kandahar.
Just across the mountains, along a proper road, there is the Pakistani city of Quetta, where the Afghan Taliban ruling council, the Shura, are thought to spend much of their time - directing and supplying their war effort against the Americans and the British from a safe distance.
And Quetta is not in the ambiguous "tribal areas" - it is proper Pakistan; it is the capital of the fully-fledged Pakistani province of Baluchistan.
It would be entirely rational for Pakistan to support the Afghan Taliban - they have to hedge their bets.
The Taliban might rule Afghanistan again one day, and they need to have a good relationship with them, as they did before, when the Taliban were in power in Kabul.
Pakistan was one of the few countries to recognise the Taliban government - there was a Taliban embassy in Islamabad.
But it does mean American and British troops are being killed because Pakistan, in effect, has failed to shut down the Afghan Taliban supply lines from Pakistan into Afghanistan.
And looking at the map highlights another point - Afghanistan is landlocked.
The Americans and the British and the rest of ISAF - the International Stabilisation Assistance Force - get most of their supplies by road.
For years, lorries lumbering across the Khyber Pass with food, bottled water and groceries for the Western forces were attacked by the Taliban.
Now many more of those lorries are getting through untouched because security firms hired by the Americans and the British are paying the Taliban huge sums in protection money to let the lorries through.
And what do the Taliban do with the cash? They probably do not take holidays at beach hotels in Dubai.
So again, American and British soldiers are being killed with ammunition paid for, indirectly, with American and British money.
You could not make it up.
Meanwhile, in Kabul, life hardly improves. Poverty in parts of the Afghan capital is almost medieval.
Begging is commonplace in poverty-stricken Kabul
"Old alms seekers with their seamy palms out-held and maimed beggars sad-eyed in rags and children asleep in the shadows with flies walking their dreamless eyes.
"Naked dogs that seem composed of bone entirely and small orphans abroad like irate dwarfs."
That is an extract from the novel Blood Meridian, by Cormac McCarthy - king of bleak.
I was reading that passage in Afghanistan last week after an afternoon walking around the capital and I thought: "That's Kabul."
But he was describing Mexico City 150 years ago.
To complete the Kabul picture you simply need to add:
Children in rags tug at your coat and you fish out a battered Afghan note worth barely 50p.
Then there are 10 small children grabbing at your hand and you cannot get away because the children are blocking the pavement.
And the road is a stream of rainwater, sewage and mud.
A woman with a baby under her burka sees you giving money to the children and begs for some herself.
And when you say you have no more one small boy persists and walks with you for 20 minutes until you relent and your reward is a genuine smile of gratitude.
The daylight thickens into night and there are no street lights.
By the glow of a storm lantern men sift through second-hand clothes on a cart and try to pick out a good winter coat.
Meanwhile, a young man desperate for work weeps as he talks to me and through accusing tears says: "You've been here eight years now, and what have you done?
"Why is my country so miserable?"
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