No president is well-served by groupthink or by everybody singing from the same sheet of music they think he's on.

I think it's kind of a stretch. You know, it's one thing if somebody working for the U.S. government has sold secrets to the other side, it's another if they have something in their personal life that they're hiding for which they could be blackmailed. Having evidence that they didn't tell the truth to somebody in the same building where they work, maybe it's just the old intel guy, is - it's a problem.

I have tried to maintain civil relationships with everyone I meet - and, even if I violently disagree with them, try to be respectful.

Some people have said, in so many words, that I'm kind of wooly-headed in believing that the Iranians would see not having nuclear weapons as more in their security interest than not.

Defense is not like other discretionary spending.

I've seen, all too often in my career, people coming in to lead agencies and organizations and trying to impose change from the top down. Never works. You never have enough time.

I think that Vladimir Putin has decided, in a very strategic way, to turn the tables and do everything in his power to, as we've described Russian elections as illegitimate, to try and communicate to the rest of the world that Western elections are illegitimate. And it's not just us, we know that now. It's Germany, it's France, it's a number of other countries.