Since 9/11 we've been engaged in wars around the world, and General [James] Mattis has been a leading battlefield commander in many of those theaters, including in the April 2004 siege of Fallujah, where the US Marines killed so many people that the municipal soccer stadium in the city had to be turned into a graveyard for the dead.

What would you do differently as defense secretary to compensate for this record in which the greatest military in the world, as we are constantly told, doesn't get the job done?

It's quite fun to fight them, you know. It's a hell of a hoot. It's fun to shoot some people. I'll be right up front with you, I like brawling.

Nothing keeps me awake at night. I keep other people awake at night.

Treachery has existed as long as there's been warfare, and there's always been a few people that you couldn't trust.

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.

Actually, it's a lot of fun to fight. You know, it's a hell of a hoot.