When people see opportunity, when they have a sense of control of their own destiny, then they're less vulnerable to the propaganda and twisted ideologies that have been attracting young people - particularly being turbocharged through social media.

I don't regret at all saying that if I saw Bashar al-Assad using chemical weapons on his people that that would change my assessments in terms of what we were or were not willing to do in Syria.

We may never understand what leads anybody to terrorize their fellow human beings. Such violence, such evil is senseless. It's beyond reason.

I would say of all the things that have happened during the course of my presidency the knowledge that you have hundreds of thousands of people who have been killed, millions who have been displaced, [makes me] ask myself what might I have done differently along the course of the last five, six years.

We wouldn't even be where we are had it not been that 70% of Hispanics voted for President Obama, voted Democratic in the last election. That caused an epiphany in the Senate, that's for sure. So all of a sudden we have already passed comprehensive immigration reform in the Senate. That's a big victory.

We've evolved a lot since 9/11 also, in terms of our law enforcement capabilities, our intelligence capabilities, military, counterterrorism.

The Russians don't make determinations about what our defense posture is.