Progress in Iraq has always been about teams of people and teams of teams - and ultimately about young men and women, Iraqi as well as people from the coalition.

The progress in Iraq is still fragile. And it could still be reversed. Iraq still faces innumerable challenges, and they will be evident during what will likely be a difficult process as the newly elected Council of Representatives selects the next prime minister, president, and speaker of the council.

There are some ideas that will translate from Iraq to Afghanistan and there are many that will not. The first lesson of counterinsurgency, in fact, is that every situation is truly unique, has its own context, its own specific set of factors - and you have to understand that context in enormous detail to be able to craft a sound and comprehensive approach.

US Ambassador to Iraq Ryan Crocker and I have repeatedly sought to emphasize that the progress in Iraq is fragile and also, possibly, reversible.

There is no military solution to the challenges of Syria.

Afghanistan has other enormous challenges as well, including a political system that is still very much developing, although there has been some progress in the past several years.

The Islamic State fighters in Mosul are dead men walking and I think they increasingly know it.