I fired a lot of senior people myself and I think the key, when you feel compelled to remove a senior official, is essentially to have all your ducks in a row at the beginning. Have everybody understand what the rationale was.

Future U.S. political leaders – those for whom the Cold War was not the formative experience that it was for me – may not consider the return on America’s investment in NATO worth the cost.

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 one concern is that Hu Jintao may overestimate how much power China has in Pyongyang. They have - they do have influence, and they do have companies, and they do have economic relationships that could make life much more difficult in the north. Their balancing act is, "How much worse can we make it in the north without creating that which scares us more than anything, which is a collapse in the north." And then what happens to all those nuclear weapons. So they're going to work very hard to avoid that.

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.

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.

Soviet foreign ministers would come in to see the president all the time, routinely. Jimmy Carter stopped that after the invasion of Afghanistan. Ronald Reagan resumed it in 1984, I think. And so the fact of a meeting like that I think is not that big a deal.