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.

My last visit to China as secretary, January of 2011, I told President Hu Jintao, just like this, "President of the United States wanted me to tell you that we now consider North Korea a direct threat to the United States." And it had no effect whatsoever.

When I was the director of Central Intelligence in the early '90s, I tried to get the Air Force to partner with us in building drones. And they didn't want to, because they had no pilots.

I had no difficulty as Secretary of Defense moving from the Bush administration to the Obama administration.

And so the greatest of American triumphs... became a peculiarly joyless victory. We had won the Cold War, but there would be no parades.

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?

I didn't think this whole business with Director James Comey was handled well. So there are sort of day-to-day aspects of the operation that I think are really troublesome. And I know that there are a lot of people in the country who have lots of issues with decisions that Donald Trump has making on the domestic side.