I think, broadly speaking, the US military's role - US military activism in various parts of the Islamic world over the past several decades has been counterproductive.

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.

We do everything humanly possible, consistent with military necessity, taking many chances to avoid civilian casualties, at all costs.

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.

I think as we look at this problem of ISIS, it's more than just an army. It's also a fight about ideas. And we have got to dry up their recruiting. We have got to dry up their fundraising. The way we intend to do it is to humiliate them, to divorce them from any nation giving them protection, and humiliating their message of hatred, of violence. Anyone who kills women and children is not devout. They have - they cannot dress themselves up in false religious garb and say that somehow this message has dignity.

There are some people who think you have to hate them in order to shoot them. I don't think you do. It's just business.

We have the most skillful, firecest, and certainly the most ethical ground forces in the world... I'm not saying we have to commit right now, but certainly don't pull it off the table.