Wasn't that the plan all along?
Create a vacuum in the heart of the Mideast to suck in all of the Islamist dust bunnies from the surrounding terror havens such as Syria, Iran, Saudi Arabia, the Palestinian Territories. Then kill them once they were in one place. Fighting them on the plains of Iraq would be much easier than in the mountains and caves of Afghanistan. Had we not gone into Iraq, these same fighters would now all be in Afghanistan waging their jihad.