The harder they hit, the more encouraged I get.

That is the number-one threat we face in the world. And it becomes particularly threatening if terrorists ever get their hands on any nuclear material. So a man who can be provoked by a tweet should not have his fingers anywhere near the nuclear codes, as far as I think anyone with any sense about this should be concerned.

I have a difference with Senator [Bernie] Sanders, who promises free college, which, if you look at the fine print, depends really on governors coming up with a lot of the money, which I don't think is a particularly wise bet. And I have a plan to help people pay down their student debt, because I want to unleash the entrepreneurial energy that young people have.

In too many instances, the march to globalization has also meant the marginalization of women and girls. And that must change.

There's the continuing challenges of racism, of sexism, of discrimination against the LGBT community, of the way that we treat people as opposed to how we want to be treated.

We do always have to make sure we keep people safe.

At the end of the day, you have to be yourself, you have to say and stand for what you believe in, you have to be willing to get up and go ahead and take the slings and arrows and just try to persist through them, because it's apparently an inevitable part of our American democracy.