Leading the coalition military effort during the surge in Iraq in 2007 and 2008 was the most important endeavor - and greatest challenge - of my 37 years in uniform.
The bottom line is that Daesh's defeat requires not just hammering them on the battlefield but, simultaneously, revived political reconciliation with Sunnis.
In the 101st Airborne Division headquarters in Mosul, we had a sign on the wall. It was a question that we would ask ourselves before every new operation or policy initiative. It asked: Will this policy or operation take more bad guys off the streets than it creates by its conduct?
Reconciliation is what takes place, of course, at higher levels. President Karzai has been very clear about the red lines for reconciliation, accept the constitution, lay down their weapons, cut their ties with al Qaeda and essentially become productive or at least participating members of society in that regard.
Items of interest will be located, identified, monitored, and remotely controlled through technologies such as radio-frequency identification, sensor networks, tiny embedded servers, and energy harvesters - all connected to the next-generation internet using abundant, low-cost, and high-power computing.
Leadership is an individual sport, one that has to be fine-tuned to each of the people that reports to you. Leaders also need to provide the direction, energy, encouragement and inspiration for each person who reports directly to the leader as well as for the overall organization.
President Obama has said that our aspirations should be realistic. We are not going to turn one of the poorest countries in the world, that was plunged into 30 years of war, into an advanced, industrialized, Western-style democracy. What we want to achieve is Afghanistan's capacity to secure and govern itself.
We cannot kill or capture our way out of an industrial-strength insurgency.
Over time, the desire of Iraqis to contribute to their own security has manifested itself in citizens volunteering for the police, the Army, and concerned local citizen programs.
The tragedy is that political leaders failed so badly at delivering what Iraqis clearly wanted - and for that, a great deal of responsibility lies with Prime Minister Maliki.
Partners from the Islamic world are of particular importance. Indeed, they have huge incentives to be involved, as the ongoing struggles are generally not clashes between civilizations. Rather, what we are seeing is more accurately a clash within a civilization: that of the Islamic world.
Ungoverned spaces in the Islamic world will be exploited by people who wish us ill. They will not be contained.
As we used to say when I was privileged to be the commander there, Nineveh province has the most diverse human terrain in all of Iraq - Sunni Arab majority to be sure, but also Shia Arabs, numerous Kurdish communities, and they are broken out into several different political parties.
It wasn't just Shia that would go to Tehran and see the commander of the Quds Force and others and the legitimate government leaders. It was also Kurdish leaders and Sunni Arabs who would even link up with Qassim Suleimani, the commander of the Quds Force - maybe not in Tehran but in Turkey or somewhere else.
There is nothing I can do to undo what I did. I can only say again how sorry I am to those I let down and then strive to go forward with a greater sense of humility and purpose, and with gratitude to those who stood with me during a very difficult chapter in my life.
I really started to get a sense of how, if you will, special Zarqawi was, I guess, sort of midway through 2004.
Needless to say, it was the greatest of privileges to serve with the selfless men and women - Iraqi and American and those of our coalition partners, civilian as well as military - who did the hard, dangerous work of the surge. There seldom was an easy period; each day was tough.
The Orlando terrorist is an example of someone who was in the sights of law enforcement but never crossed the threshold from pre-criminal to criminal behavior and, thus, was not tracked adequately before this horrific act.
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.
The Pakistani Army, the Frontier Corps, the Frontier Scouts and Police have carried out quite impressive counter-insurgency operations.