let's just do a thought experiment.
what is our most important interest in the geopolitical control of the middle east?
if iraq had no oil, would we have intervened?
you know, i know, everybody know the answers to these questions. ergo, the major reason for going to iraq is control of the most important resource on earth over the next 20 years: oil.
now there may be other less important reasons but it does not change the above.
if iraw was completely unarmed, would we have invaded... nice try ace...