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.

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.

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 consider myself a Republican.

On the foreign policy side, there's the risk of being too spontaneous and too disruptive where you end up doing more harm than damage. And figuring out that balance is where having strong people around you matters.

There's a lot of books out there about how you lead change in business, but I've certainly not seen any... on how you do that in public institutions.

Things have gotten so nasty in Washington.