IMHO, Bush II should have declared war against the Taliban right after 9/11.
It was an operation Financed and Perpetrated by the House of Saud, and that is who the declaration should have been against. The Taliban is a Straw Man.
There is evidence pointing in that direction. But what would their motive be? Certainly the Saudis feared Saddam's Iraq, but why would they want us to get involved in Afghanistan instead?