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?

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.

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 don't know General Michael Flynn well, but it's hard for me to believe anybody would allow themselves to be blackmailed by the Russians because they didn't tell the full story or didn't tell the truth to the vice president of the United States who works 50 feet down the hall.

If Iraq and Afghanistan have taught us anything in recent history, it is the unpredictability of war and that these things are easier to get into than to get out of, and, frankly, the facile way in which too many people talk about, 'Well, let's just go attack them.

I'm a big advocate of drones.

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