There is no international problem that can be addressed or solved without the engagement and leadership of the United States and everybody in the world knows that, its just fact of life. So sometimes I think we could conduct ourselves with a little more humility.

It has become clear that America's civilian institutions of diplomacy and development have been chronically undermanned and underfunded for far too long - relative to what we spend on the military, and more important, relative to the responsibilities and challenges our nation has around the world.

I will always be an advocate in terms of wars of necessity. I am just much more cautious on wars of choice.

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.

Some people have said, in so many words, that I'm kind of wooly-headed in believing that the Iranians would see not having nuclear weapons as more in their security interest than not.

Defense is not like other discretionary spending.

Power... Military success is not sufficient to win: economic development, institution-building and the rule of law, promoting internal reconciliation, good governance, providing basic services to the people, training and equipping indigenous military and police forces, strategic communications, and more of these, along with security, are essential ingredients for long-term success.