I think its pretty much a safe bet that US troops will be there for years (maybe mostly in Kuwait, perhaps some in Tikrit and/or Kurdistan)

since wwII this region has been of strategic importance no matter what US administration is in charge. And it will remain to be even if we switch to renewable energy - because by controlling it you can deny power to others.

like Noam said, if the majority of the worlds oil supply were in the south pacific, and not the middle east and the principal export of Iraq was dates, would the US be in Iraq?