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across coalition and national lines, and across civilian/military lines, you need to go home, because your leadership is obsolete.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.

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.

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

Our world is becoming darker. The dangers are increasing from North Korea, whose recent provocation underscored the need to impose a higher price on this rogue regime, a problem that is not just the United States alone, but a problem for us all.

I was struck by the fact that none of the senators, basically, asked General [James] Mattis, "Well, General, how is it that we haven't won?" We haven't won anywhere, 'winning' in the sense of conclusively achieving our political objectives, however you might want to define those objectives.

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

I would happily storm hell in the company of these troops ... how strongly they have demonstrated to the world that free men and women can fight like the dickens.