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.

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.

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.

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

I had no difficulty as Secretary of Defense moving from the Bush administration to the Obama administration.

I think that Iran with a nuclear weapon is extremely destabilizing. I think it could precipitate a nuclear arms race in the region.

I think it's kind of a stretch. You know, it's one thing if somebody working for the U.S. government has sold secrets to the other side, it's another if they have something in their personal life that they're hiding for which they could be blackmailed. Having evidence that they didn't tell the truth to somebody in the same building where they work, maybe it's just the old intel guy, is - it's a problem.