The Taliban, and the chaos out of which they emerged, were the outcome of the combined cackhandedness of the Russians and the USA. Here is an extract from an article in today's Guardian:

"The Russians... had the support of many urban people, particularly in Kabul. This is why their ally, Najibullah, survived three years after the Russians left...

When the Russians withdrew, they hoped the US would see the benefit of modernisation and encourage the least extreme of the mojahedin to share power with the-then ruler, Najibullah. But Washington was divided between "bleeders", who wanted to exploit Afghanistan to humiliate Moscow, and "dealers", who saw value in keeping the fundamentalists at bay. The bleeders won, paving the way for the Taliban's eventual triumph. So Bin Laden's safe haven in Afghanistan was provided as the result of US policy - not in spite of it."

And the essential lesson which never seems to be learned is that the old dictum "My enemy's enemy is my friend" can never be trusted. If the people running things don't appreciate that, they are just going to sow the seeds for things that could be even worse in the future.