Yousef Aid Ahmed has memorized the places where his four brothers' bodies laid after they were killed by US marines, he said. The family recounts that November day in 2005 and says it was a massacre of the brothers, along with 20 other people, following a roadside bomb in Haditha.

The destruction that we have wreaked in the various theaters in which we've been engaged is really quite astonishing. But again, lethality, destruction, killing doesn't seem to achieve our objectives. So, my own sense is that a lack of lethality does not define the core problem.

There is nothing better than getting shot at and missed. It's really great.

General [James] Mattis's primary experience - indeed, his only experience - is as a member of the United States Marine Corps, where he served for 41 years. That's his experience.

In this age, I don't care how tactically or operationally brilliant you are, if you cannot create harmony - even vicious harmony - on the battlefield based on trust across service lines, across coalition and national lines, and across civilian/military lines, you need to go home, because your leadership is obsolete. We have got to have officers who can create harmony across all those lines.

The most important six inches on the battlefield is between your ears.

If in order to kill the enemy you have to kill an innocent, don't take the shot. Don't create more enemies than you take out by some immoral act.