I plead - that it's very difficult when you deal with - ISIS and organizations like that whose - whose behavior is so barbaric and so vicious - that it doesn't seem to have any purpose other than lust for killing and power. And that's very difficult to put ourselves in other shoes.

There's a different leader in Syria now. Many of the members of Congress of both parties who have gone to Syria in recent months have said they believe he's a reformer.

I think wherever we can cooperate with Russia, that's fine. And I did as secretary of state. That's how we got a treaty reducing nuclear weapons. It's how we got the sanctions on Iran that put a lid on the Iranian nuclear program without firing a single shot.

I hope the fact-checkers are turning up the volume and really working hard. Donald [Trump] supported the invasion of Iraq.

I think Americans have every reason to be worried about ISIS and the network of terrorist groups, because they have proven to be sophisticated and effective in wreaking violence and murder in many parts of the world, including in San Bernardino with their somehow connected radicalization of that couple there.

I don't feel particularly courageous.

All of us have to recognize that we owe our children more than we have been giving them.