The US and UK got things so wrong in Afghanistan because they do not understand the Afghan way of war

The country is unlikely to become a haven for terrorists again as the Taliban no longer needs help from al-Qaeda

The American way of dealing with a lost war is to withdraw its forces. The Afghan way of dealing with it is to change sides as quickly as possible.

The Afghan way of war has created confusion among foreign political and military leaders in the past 20 years, but never more so than during the past few weeks as the Taliban swept through the country, capturing city after city without facing serious resistance.

Intelligence agencies had generally assured western leaders that the Afghan government had the soldiers and weapons to make a fight of it. They did so, even after president Joe Biden announced on 14 April that all American troops would be out of Afghanistan by the 20th anniversary of 9/11. Biden said that a Taliban victory was not “inevitable” and Boris Johnson added that the Taliban had “no military path to victory”. Experienced politicians do not make such confident predictions unless their intelligence chiefs have been telling them the same thing.

The reason so many well-informed people got it so wrong is that they were comparing the military strength of the two sides. But the Taliban victory was not military so much as political. Analysts now wring their hands and explain that Afghan soldiers often were not paid and lacked supplies of food and ammunition. It is also true that the Afghan army had become accustomed to calling in close American air support and felt bereft without it.

The political triumph of the Taliban came about because Afghans with power – military commanders, civilian officials, tribal leaders, local warlords – decided that the US had done a deal with the Taliban and they would be wise to follow suit as quickly as possible. They saw president Donald Trump make concession after concession in negotiations with the Taliban in Qatar without the Afghan government getting anything in return. Biden confirmed this approach when, for domestic political reasons, he decided to grandstand in announcing a complete US pull out.

The most striking feature of the Taliban seizure of power is that it took place with so little fighting. This was the case even in what were once the heartlands of anti-Taliban resistance before their overthrow by the US-backed Northern Alliance in 2001. Easily defended mountain strongholds in the Hindu Kush and large anti-Taliban cities like Herat and Mazar-i-Sharif fell after a few days fighting or without a shot being fired.

The speed and ease of the Taliban advance was self-fulfilling as Afghans became convinced that they were going to be the winners. Deals were done with powerful warlords – or their underlings – who had been expected to resist. This repeated the pattern of the 1990s when the Taliban first took power in the country. At that time cities and towns often changed hands because the Taliban simply paid their enemies to go home. It would be surprising if this has not happened again.

These changes of allegiance sped the Taliban on their way to Kabul, but the loyalty or neutrality of their new fair-weather adherents is shallow. They will expect to retain their old control under the loose authority of a Taliban central government. Moreover, it may be difficult for the largely Pushtun Taliban to rule Tajik, Uzbek and Hazara areas without conceding a high degree of autonomy to them. The risk-laden alternative for the Taliban would be to use extreme violence against Afghanistan’s minorities, but the Tajik, Uzbek, Hazara and other smaller groups collectively make up not far from 60 per cent of the population.

The Taliban has one important advantage in holding onto power. For the moment, no foreign power or neighbouring state looks likely to support an anti-Taliban resistance movement with arms and money. They won power in the 1990s because of backing from Pakistan and lost it in 2001 because the US backed the Northern Alliance.

The US, Britain and other states warn that they will not tolerate Afghanistan becoming once again a haven for terrorists, as it was when Osama bin Laden and al-Qaeda were based in the country.

But this time round the Taliban is eager to win international recognition as the legitimate government of Afghanistan. They would pay a heavy price in terms of international isolation if they host al-Qaeda or Isis.

Another argument against other jihadi organisations again congregating in Afghanistan is that 20 years ago, when Osama bin Laden had his headquarters and camps there, an alliance with him was a two-way street. The Taliban gave him refuge, and he gave them money and a core of fanatical fighters. It was, after all, two al-Qaeda suicide bombers who assassinated the Northern Alliance leader Ahmad Shah Massoud, just prior to 9/11.

But the Taliban no longer need help from al-Qaeda and there is every reason why they should reject a renewed alliance. On the other hand, there may be Taliban commanders who feel ideologically akin to al Qaeda and its clones and will give them covert aid.

The Taliban are visibly astonished by the completeness of their victory and will take time to digest and consolidate it. The outside world will be wondering what to make of the new Afghan regime and what will be the implications of its success for them and for the region.

It is in the interests of the Taliban for the moment to show a moderate face, but they have fought a ferocious war for two decades, taking heavy casualties. There will be many in their ranks who do not wish to dilute their social and religious beliefs for the sake of politically convenience. Despite the amnesty just declared by Taliban leaders, many will seek vengeance against former government supporters whom they have long denounced as traitors.