Iran is a state sponsor of terrorism. And for them to be able to provide nuclear technology to non-state actors, that's unacceptable.

You mentioned the Navy, for example, and that we have fewer ships than we did in 1916. Well, Governor, we also have fewer horses and bayonets because the nature of our military has changed. We have these things called aircraft carriers where planes land on them. We have these ships that go underwater, nuclear submarines.

I don't take a dime of their [lobbyist] money, and when I am president, they won't find a job in my White House.

It was into my father's image, the black man, son of Africa, that I'd packed all the attributes I sought in myself, the attributes of Martin and Malcolm, DuBois and Mandela.

We've got to make sure that we rebuild the infrastructure in America, because we used to be - have the best bridges, the best roads, the best airports. And now, when you go to China or you go to Europe, you see that they are outstripping us in terms of infrastructure. And if we put people back to work, that would be good not only in the short term, but it would also lay the foundation, the framework for long-term economic and job growth.

There's no doubt that I'm a better president now than when I first took office. This is not a job where there's a manual, and over time you get a better sense of what's important, what's not, how to see around corners and anticipate problems, as opposed to just managing problems once they've arrived.

So don't get cynical. Cynicism didn't put a man on the moon. Cynicism has never won a war, or cured a disease, or built a business, or fed a young mind. Cynicism is a choice. And hope will always be a better choice.