What I know concerns me. What I don't know concerns me even more. What people aren't telling me worries me the most.

It's clear the relationship between China and North Korea has hardly ever been worse. Kim Jong-un has never been to Beijing in his leadership. The Chinese press are saying some amazingly negative things about the north, and about Kim Jong-un. So - so they are weighing in, and they are bringing greater pressure. Whether it will be enough I think remains to be seen.

I think that Vladimir Putin is certainly getting a lot of publicity for what the Russians are doing. And I'm not sure that's unwelcome to him. I think this is a guy who saw the U.S. basically come out against him in his reelection campaign in 2012. He saw the U.S. being behind all of the color revolutions in Eastern Europe and in Georgia and Ukraine and so on. So his view is the West has been interfering in his politics for years.

Well, what I've said is that the war in Iraq will always be clouded by how it began, which was a wrong premise, that there were in fact no weapons of nuclear - weapons of mass destruction.

Congress is best viewed from a distance—the farther the better—because up close, it is truly ugly. I saw most of Congress as uncivil, incompetent at fulfilling their basic constitutional responsibilities (such as timely appropriations), micromanagerial, parochial, hypocritical, egotistical, thin-skinned and prone to put self (and re-election) before country.

Defense is not like other discretionary spending.

I think in the context of senior government positions, I think an anecdote of what I told President-Elect Barack Obama when we had our first meeting. And I said, "You don't know me. Can you trust me? Why do you think you can trust me?" and so on. But at the end, I said, "You can count on me to be loyal to you. I will not leak. I will keep my disagreements with you private. And if I cannot be loyal, I'll leave." Loyalty means doing what you think is in the best interest of that person as well as the country.