Sometimes if your only approach is cutting spending at a time when the economy's contracting, then the economy will contract further.

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.

To young people: you have to stay encouraged.

Today, more than ever before, science holds the key to our survival as a planet and our security and prosperity as a nation. It's time we once again put science at the top of our agenda and work to restore America's place as the world leader in science and technology.

We've subsidized oil companies for a century. That's long enough. It's time to end the taxpayer giveaways to an industry that rarely has been more profitable, and double-down on a clean energy industry that never has been more promising. Pass clean energy tax credits. Create these jobs.

We want our children to live in an America...that isn't threatened by the destructive power of a warming planet.

[When I ordered 30,000 more troops into Afghanistan] that was the first time in which I looked out at a crowd of West Point graduates and knew that some of those might not come back because of that decision.