Pak played it evil. Kept Pakhtuns busy fighting Kashmir, and then among ourself, and then Soviet and then ourself again. The unstability of Afghanistan was boon of Pak in 80's and they continued to abuse our islam to keep Afghan unstable in 90's more so when treaty got over and Pak had to give us back our land. With Taliban Govt under Pak Army govt Afghanistan never got her lands back. And Pak should stop keeping us unstable, but Pak will try to do so again, so that we don't get our land's back.
http://www.afghanland.com/history/durrand.html
http://www.janrainwater.com/htdocs/afghan2p1.htm