The Sunni Arabs began to realize that they had made a huge mistake by not voting in the election of 2005 and by not being part of the new Iraq. They had reasons for this: They were effected by the disestablishment of the military and by de-Baathification (the dismantling of Saddam Hussein's party) in winter 2007-2007. They increasingly recognized that their future lay in being part of the solution rather than a continuing part of the problem.

ISIS is on its way to defeat but terrorism threat persists.

The president and I sat down in the Oval Office, and he expressed very clearly that what he wants from me is my best professional military advice.

I did a week-long assessment in 2005 at (then Defense Secretary Donald) Rumsfeld's request. Following our return, I told him that Afghanistan was going to be the longest campaign of what we then termed "the long war."

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 has, indeed, been very substantial progress in Iraq over the past year - violence is down by 80 percent, civilian deaths by about the same, and so on.

Political progress will only take place if sufficient security exists.