I mean, when you get down to very low numbers of nuclear weapons, and you contemplate going to zero, how do you deal with the reality of that technology being available to almost any country that seeks to pursue it? And what conditions do you put in place?

In government, I'm a strong believer in the need for reform of government agencies and departments. They - they have gotten fat and sloppy, and they're not user friendly. They are inefficient. They cost too much.

There is no international problem that can be addressed or solved without the engagement and leadership of the United States and everybody in the world knows that, its just fact of life. So sometimes I think we could conduct ourselves with a little more humility.

Even when I was at CIA, I'd go to visit foreign leaders and I'd say, 'You know, I'm not a diplomat. I'm just an old CIA guy'... I said, 'If I wanted to be diplomatic, I'd have been a diplomat.'

Well, I've ruffled a few feathers at all the institutions I've led. But I think that's part of leadership.

I think, on the foreign policy side, that there is a need for disruption. We've had three administrations follow a pretty consistent policy toward North Korea, and it really hasn't gotten us anywhere.

I wish I could set deadlines for the Congress, but that's just not the way the Constitution is written.