...and those costs would be dwarfed if the U.S. took on a war on Iran, which event would really be the logical outcome of the neo-con "secure foreign policies" of the Bush Jr presidency (an outlook which is deeply grounded in much of the Republican party).Yikes.

I don't think it's very likely that the US would pull out all military presence from Iraq in two years even if there is a Democrat President from next January; the country matters too much, both economically and strategically - neighbour of Iran, Syria and the Russian Caucasus fringe - to give up control. And even though imo it's an illegal occupation following a war that was illegal and misguided from day one, I'm not sure a sharp pull-out now would be that good. Surely it wouldn't solve many problems? With almost 100% certainty it would leave Iraq spiralling further into civil war, and that in itself would help breed new terrorist groups. When you've taken the Devil into your boat you have to row him ashore! It seems to me one has to bring new partners into this,. possibly the UN or the Arab League but neither will be easy of course. Iraq will likely remain a burning wound for a long time.