Have you ever wondered why al Qaeda and other Islamists are moving into Iraq in force to fight us?

No, I never have. They are going there to fight us because we are there. We weren't there before, so the opportunity didn't exist.

Did you ever wonder why they aren't putting the same effort into Afghanistan to face the much smaller forces there, if they have no concern over a liberated Iraq, and the goal is just to defeat us?

No, I haven't. They didn't have to go to Afghanistan because they were already there. Their concern over a liberated Iraq could be as simple as making sure that the US doesn't have access to the fuel to drive out culture. Iraq, furthermore, is a lot easier to get into and out of, as the physical problems of the Hindu Kush do not apply as they do in Afghanistan.

Also, they may have studied the history of Afghanistan, a fractious nation of war lords and tribal enemies who fight endlessly among themselves and only unite to fight a foreign foe. You can ask the British Raj and the Soviets about that. Americans dominate Afghanistan? Ha! The last one to do that, for about two years, was Alexander the Great, and he had to marry a chieftan's daughter to do it. The lovely Roxanne.