We've got to remain energy-independent. It gives us much more power and freedom than to be worried about what goes on in the Middle East. We have enough worries over there without having to worry about that.

If you are too dangerous to get on a plane, you are too dangerous to buy a gun.

As president, I will appoint tough, independent authorities to strengthen anti-trust enforcement and really scrutinize mergers and acquisitions, so the big don't keep getting bigger and bigger.

I have pretty thick skin. I've been in the arena a long time, and that means that I am not going to get down with [Donald Trump] and go insult for insult.

I think that we have to look at ISIS as the leading threat of an international terror network. It cannot be contained, it must be defeated.

The middle class is both real and aspirational. And I want to make sure that it remains strong and it gives people a sense of security and confidence and optimism about their futures.

Historically, it is important to try to understand your adversary in order to figure out how they are thinking, what they will be doing, how they will react.