President Barack Obama started by accepting the military's counterinsurgency, but came out of Afghanistan having decided that counterinsurgency actually doesn't work.

I think President Barack Obama came to office with quite fundamental understandings in his mind about what's possible and what's not possible in the Middle East. The first, I would say, revolutionary breakthrough that he introduced is that the Middle East doesn't matter to American geostrategy as much as we think.

What you have in Iraq is not just a society coming apart like Yugoslavia or Congo. What is at stake is not just Iraq's stability but the balance of power in the region.

My time in the Obama administration turned out to be a deeply disillusioning experience.