We didn't used to deal with terrorism by going to war. At least not until the Wolfowitz/Bush doctrine was put into play. Instead of trying to militarily destroy a group of countries in an attempt to wipe our enemies off the map, we used to bomb the heck out of them.

It was the actions of Reagan sending F111's to Libya*, in retaliation for the disco bombing, and the failed attempt by Clinton to bomb a suspected chemical plant in Sudan that set the stage for how to deal with terrorism.

Our response to the destruction of the Twin Towers and 3000 lives should have been more like how we conducted First Gulf War. It was a multi-nation action against a military aggressor, albeit a much clearer objective than fighting a dispersant enemy that is only distinguishable from the population when they shoot at us.

The gulf war lasted eight months. Our mission in Afghanistan should have been to punish and leave.
Even if only to satisfy the need for demonstrating our power, revenge for 911, and to help heal the national psyche.

(*I'll never forget when France and Italy wouldn’t allow us to use their airspace)