The war in afghanisatn has been older then the US / USSR tusle … it goes back to the british and Russians … the great game … US just picked up from where Britian had left.
As for the role of Pakistan. After the end of soviet era … they had to do something as it was getting stategically difficult for them. The groups that they had supported with the US money were not listening to them … also you have to keep in mind a hostile afghanistan is very dangerous for Pakistan. You have teh issue of Durand line & also they have to divert resources from the east … Indian side … to defend from afghan border.
So it had become a necassity for them to do somthing in reference to Afghansitan. US had no interest and they would have supported any move by Pakistanis in afghansitan. So they bank rolled and supported one of the newly formed groups called Taliban. A group formed of some old mujahedins AND a lot of new recruits from madrasas in Pakistan.
The chaos that was in Afghanistan was because of the old mujahedins … most of these old mujahedis were the warlords protect their piece of pie in Afghansitan. At this time i would add that a number of countries including Iran, India, Russia through its satellite states were adding to this pot boiler.
So this was the ripe situation for someone to come as a protector of people … so the Taliban rode into a situation which was tailor made for them … the incorruptable islamic jehadis … whose sole aim as to unify Afghanistan.
Role of Pakistan in this is widely known … i have added links and mentioned from reports above and can add a lot more.
So now these talibans have turned on their maker … hence the lesson
Here is something more to chew on