You came with what purpose ? To get rid of OBL ? That purpose could have been achieved if the Taliban had been offered the evidence they sought to repatriate him to a Muslims country (insert Saudi Arabia).
What you guys instead did was bomb a country to nothing, killed so many Afghans & Pakistanis, lost so many American soldiers in turn, raked up more debt than anything you ever had, lost yet another war only to masquerade as an after-thought as if you won & destabilized the region for generations to come.
And for what ? Doing in 2012 what Pakistan asked you to do in '01 - Talk to the Taliban !
And why would the country not fall back into a civil-war ? Whole swathes of Afghanistan are under Taliban control & those blasted Warlords were the ones who fought each other to the ruining of their country in the early '90s. I'm sure you've brought stability to those lands !