Donald Trump is like Hillary Clinton said, a man you can bait with a tweet is not a man you can trust with nuclear weapons. You can`t do it.

If you think that running your economy into the ground and having to send troops in in order to prop up your only ally is leadership, then we've got a different definition of leadership.

When we think of the major threats to our national security, the first to come to mind are nuclear proliferation, rogue states and global terrorism. But another kind of threat lurks beyond our shores, one from nature, not humans - an avian flu pandemic.

Young people recognize the big challenges that are coming up.

It's good to get fresh legs in [the White house]. I think that it refreshes our democracy.

You could analyze me and say that my father leaving and being absent was a motivator for early ambition, trying to prove myself to this apparition who had vanished. You could argue that me being a mixed kid in a place where there weren't a lot of black kids around might have spurred on my ambitions. You could go through a whole litany of things that sparked me wanting to do something important.

If you've got a business, you didn't build that. Somebody else made that happen.