There have been four foreign invasions of Afghanistan in less than 200 years. The first two were British, and unashamedly imperialist. The third was Soviet, and the invaders said they were there to defend socialism and help Afghanistan become a modern state. The last was American, and the invaders said they were there to bring democracy and help Afghanistan prosper. But all four invasions were doomed to fail (although the last still has some time to run).

When Britain deployed 3,300 troops to Helmand province early last month, then defence secretary, John Reid, said: ?We hope we will leave Afghanistan without firing a single shot.? But six British soldiers have been killed in combat since then, and the new defence minister, Des Browne, announced that the British force is being increased by another 900 soldiers to cope with ?unexpected? resistance.

The story is the same across southern Afghanistan. The Canadian army has lost six soldiers in Kandahar, and may soon face the same choice between reinforcing its troops or pulling them back, because the American combat troops in the vicinity are leaving at the end of this month. The US forces are pulling out just in time.

A country that has been invaded four times in less than two centuries is bound to know a couple of things about dealing with foreign conquerors. The first thing Afghans have learned is never to trust them, no matter how pure they say their intentions are. There are probably no more xenophobic people in the world than the Afghans, and they have earned the right to be so.

New beginning

The other thing Afghans know is how to deal with invaders. They will always be richer and better armed, so let them occupy the country. Don?t try to hold the cities; fade back into the mountains. Take a couple of years to regroup and set up your supply lines, and then start the guerilla war in earnest. Ambush, harass and bleed the foreigners for as long as it takes. Eventually they will cut their losses and go home.

The end-game is beginning even in Kabul. Hamid Karzai, the West?s chosen leader for Afghanistan, is now starting to make deals with the forces that will hold his life in their hands once the foreigners leave: the warlords and drug barons. In April, he dropped many candidates who had been approved by the ?coalition? powers from a list of new provincial police chiefs, and substituted them with names of known gangsters and criminals who work for the local warlords. He will also have to talk to the Taliban before long.

The ?Taliban? that western troops are now fighting in Afghanistan is more inclusive than the narrow band of fanatics who imposed order on the country in 1996 after seven years of civil war. The current Afghan resistance movement includes farmers trying to protect their poppy-fields, nationalists furious at the foreign presence, as well as young men who just want to show that they are as brave as previous generations of Afghans.

Nor is the regime that will eventually emerge in Kabul after the foreigners have gone home likely to resemble the old Taliban, a Pakistan-backed and almost entirely pashtu-speaking organization. The foreign invasion overthrew the long domination of the pashtu-speakers in Afghanistan, and it is most unlikely that Tajiks, Hazaras, Uzbeks, and Turkmen will simply accept that domination again. Their own warlords will have to have a share of the power, too, and even Karzai might find a role.

Afghanistan will not be left to its own devices until after the people who ordered the invasion leave office: presumably next year, for Tony Blair, and January, 2009 for George W. Bush. There is time for lots of killing yet. But Afghanistan stands a reasonable chance of sorting itself out once the western armies leave.