Each of us must work to become a hardheaded realist, or else we risk wasting our time and energy on pursuing impossible dreams. Yet constant naysayers pursue no less impossible dreams. Their fear and cynicism move nothing forward. They kill progress. How many cynics built empires, great cities, or powerful corporations?

This is something else that is drilled into us in the military: Make sure you know who your replacement is, in case you become a casualty. So you have to have depth within an organization.

Some of the generals are saying, 'We're making progress. We are clearing an area.' But you really don't defeat the Taliban by clearing an area. They move.

If you get the dirty end of the stick, sharpen it and turn it into a useful tool.

Baghdad fell on April 9, 2003, Hussein and his regime were brought down, we declared "Mission Accomplished" and celebrated victory . . . and chaos erupted. We did not assert control and authority over the country, especially Baghdad. We did not bring with us the capacity to impose our will. We did not take charge. And Iraq did not in a few weeks magically transform itself into a stable nation with democratic leaders. Instead a raging insurgency engulfed the country.

Our senior officers knew the war was going badly. Yet they bowed to groupthink pressure and kept up pretenses. ...Many of my generation, the career captains, majors, and lieutenant colonels seasoned in that war, vowed that when our turn came to call the shots, we would not quietly acquiesce in halfhearted warfare for half-baked reasons that the American people could not understand.

Our failure was that our intelligence community thought [Saddam Hussein ] had stockpiled weapons of mass destruction. That was a mistake. There is fallibility in human intelligence and in human decisions.