The correct answer is - establish a democratic government.
One of the main goals of the war in Afghanistan, at least officially, was to establish a democratic government. In order to accomplish such a thing, the Us forces, as well as the others that fought alongside them, had to eliminate al Qaeda first, as well as to put under control the separatist, extremist tribes that were controlling parts of the country.
Unfortunately, this didn't really worked out as planned, and Afghanistan is still a country in terrible condition. It is still a country where the safety is on a very low level, the human rights are not respected, especially towards the women, and the existence of terrorist and extremist groups is still a huge problem.