When we attacked the Taliban in Afghanistan, it is true that US forces consisted mainly of SF and airpower. However, they worked hand-in-hand with the Northern Alliance and several other like groupings. The indigenous forces provided the conventional troops required to force the Taliban to mass so that we could hammer them with airpower. Once the Taliban figured out that they were in a no-win situation, they rapidly collapsed. In Iraq, there were no indigenous armies on the ground to provide security for the SF and force the enemy to present himself as a target. We had to provide that army.

Even if we could have crushed the Iraqis with a slightly pumped up version of Afghanistan, you still need troops to occupy the country. Those who say we did not need to occupy the country miss the point of the war in the first place: not just to topple Saddam, but to create a democratic outpost in the Middle East. Furthermore, our failure to follow up our victory in Afghanistan - due to lack of resources and troops on the ground - foreshadowed our lack of vision in Iraq. It just took longer for those particular fowl to come home to roost.

Just proof that preparing for the last war is not the sole perogative of conventional thinkers.