Durand line is the Border between Afghan and Pakti.
Afghan doesn't have the problems on their side of the Durand line than Pakti has on its side of the Durand line, same culture on both sides of the line....Pashtoon ! ? !

Geography same on both sides of border, so whats the difference? USA Forces on Afghan side, not on Pakti side.
More:
The rest of the Story
http://warintel.blogspot.com/2007/11/durand-line-talibans-stealth-border_17.html