^ The biggest failure was to let him get away when he was stuck in Tora Bora, al-Qaida was decimated and widely hated at that time, and the US had much more support worldwide. At that time, it was a complete failure at the highest levels not to send in troops instead of relying upon the untrained thugs of the Northern Alliance.
Unfortunately, now the US is considered an occupier in Iraq and Afghanistan and the resulting anti-Americanism has given al-Qaida extremist a new lease of life with a new rallying cry.