What if we went to war and in the country where the shooting was happening people had no idea why we had invaded? The United States' ten year long incursion and sporadic attempt to remake Afghanistan has achieved that end, if not much else.
Since they don't know why we are there now, Afghans are unlikely to take up any notions we might want them to assimilate when we leave.
And we will leave sooner or later -- the Afghan war is both unaffordable and unwinnable. To continue a purposeless war is also immoral.
Photo by way of ISAF Media. Taken in Helmand province, December, 2010.