The reality is, the United States has global interests. Our defense budget is about the same as the defense budgets or military budgets of every other country in the world put together.

One of the toughest battles in intelligence is combating conventional wisdom.

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.

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.

Every time we have come to the end of a conflict, somehow we have persuaded ourselves that the nature of mankind and the nature of the world have changed on an enduring basis and so we have dismantle our military and intelligence capabilities. My hope is that as we wind down in Iraq and whatever the level of our commitment in Afghanistan, that we not forget the basic nature of humankind has not changed.

Well, I've ruffled a few feathers at all the institutions I've led. But I think that's part of leadership.

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.