If there's ever an example that military power alone cannot be successful in Afghanistan, I think it was the Soviet experience.

Defense is not like other discretionary spending.

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.

In my opinion, any future defense secretary who advises the president to again send a big American land army into Asia or into the Middle East or Africa should 'have his head examined,' as General MacArthur so delicately put it.

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

I didn't think this whole business with Director James Comey was handled well. So there are sort of day-to-day aspects of the operation that I think are really troublesome. And I know that there are a lot of people in the country who have lots of issues with decisions that Donald Trump has making on the domestic side.

I think that Vladimir Putin has decided, in a very strategic way, to turn the tables and do everything in his power to, as we've described Russian elections as illegitimate, to try and communicate to the rest of the world that Western elections are illegitimate. And it's not just us, we know that now. It's Germany, it's France, it's a number of other countries.