If we want America to stay on the cutting edge, we need young Americans to master the tools and technology that will change the way we do just about everything.

We are a people of improbable hope.

We have to all shoulder the responsibility for keeping the planet habitable, or we're going to suffer the consequences - together.

It's easier to make negative attacks and simplistic slogans [in social media] than it is to communicate complex policies.

If John McCain wants to have a debate about who has the temperament, and judgment, to serve as the next Commander-in-Chief, that's a debate I'm ready to have.

I know that gaps can be closed. And they can be closed substantially, more than I think we believe.

We need to teach our kids that it's not just the winner of the Super Bowl who deserves to be celebrated, but the winner of the science fair.