What's the Real motive for the War on Terror?

Video asks many questions about what the motivations were.  Personally, I think the reason to go to remove Saddam was necessary, I do feel that the execution of the action was inadequate and possibly inept at worst.  So we look to the motivations behind the action to determine if there was a reason why the administration chose to invade Iraq with one third of the forces needed to win the peace.