Oil is too simplistic an explanation for the US invasion and it's time we started looking beyond that meme if we want a more genuine understanding of where and why the US intervenes when it does. And furthermore accept that due to the nature of our leadership, the answer is often to large degree irrational in the long term strategic sense and rooted in opportunism and idealism. How could we sustain an actual coherent strategy beyond a 2-4 year election cycle with our political setup is a **** mess, nonetheless between administrations.
If you want my take, Bush Jr's invasion of Iraq, with Cheney behind the chair, was one of those rare points of genuine continuation of strategy between administrations aided by the fact that the continuation was based off the actions of none other than his fricking dad. Dynastic relations make for funny politics. Basically my theory is that it was all a bid to try and complete what Bush Sr. started, gain prestige and an easy victory just like Desert Storm over a diplomatically isolated and vulnerable target. Little did he know how much it would blow up in his face. But to me, the other theories that get bandied about like the classic oil invasion meme just doesn't add up.