The unemployment rate today for people with our-year college degrees is 4.1%, which is almost none. That's people switching jobs basically. That tells you that education is the only way up and the only way out. If that is the fact, then we've got to get more of it for more people.

Combating climate change requires government policy, and most conservatives hate the idea of more government regulation. Because they hate the prescription, they deny the diagnosis.

Rock stars get room keys, I get business cards. Wherever I go I meet innovators of wind power equipment, solar energy operators.

Everything I’ve ever gotten in life is largely due to the fact that I was born in this country, America, at this time with these opportunities for its citizens. It is the primary obligation of our generation to turn over a similar America to our kids.

Communism was a great system for making people equally poor - in fact, there was no better system in the world for that than communism. Capitalism made people unequally rich.

We have to be the best global citizens we can be.

Pessimists are usually right and optimists are usually wrong but all the great changes have been accomplished by optimists.