I think this is the biggest lesson a president or any of us who has responsibility to govern have to learn: There are always consequences to actions that you take. There are consequences to inaction.

(The) chain of command has failed over the years, obviously, for a lot of reasons.

The president of the United States is the commander in chief, and the people who work with him at the National Security Council are his arm in working with the Defense Department. And, quite frankly, they have responsibility for all of the government. We are one component of the government.

Politics or ideology must not get in the way of sound planning.

I'm not sure leaders listen enough, especially to their people. And I've always thought in everything I've tried to do in my life, in the jobs I've had, is that if we can turn our transmitters off and our receivers on more often, we're better leaders and we know more of what is going on and therefore we can lead more effectively.

I'm the first secretary of defense that's had to deal with sequestration. I've prepared two budgets that deal with sequestration. And you bring the chiefs together, the leadership of this enterprise together, to work through, how do we then take these cuts? Where do we apply those cuts? Readiness is the first thing that suffers.

I have said many times that Iran is a state sponsor of terrorism.