Why didnt America go after Afghanistan & Pakistan instead of Wasting Time and Resource in Iraq?

By Going to Iraq, America poured oil on a fire while trying to extinguish it. America should have focused on Afghanistan, and then either invade Pakistan - they have nukes tho - or pressure Pakistan into letting US fight there....But somehow control both sides of the border itself. Then it should have focused on capturing Bin Laden. This would have ended Al Qaeda and pretty much terrorism or crazy radicals. Al Qaeda and such groups couldnt establish in the middle east because the rulers especially Saddam Hussein were at extreme odds. This is why i think the US made a pretty big mistake and it cost them a lot of losses, as well as Civilian losses.