The great thing about cheap natural gas, again it's cheap, and it provides a cleaner alternative to coal. But it's still a fossil fuel, and because it's still a fossil fuel, it still emits carbon.

Remember, the difference between the world frozen over, in an ice ball, and the warming period we're in now is just 6 degrees centigrade. A change of just 1 degree can have a huge effect.

The hidden hand of the market will never work without a hidden fist -- McDonald's cannot flourish without McDonnell Douglas, the builder of the F-15. And the hidden fist that keeps the world safe for Silicon Valley's technologies is called the United States Army, Air Force, Navy and Marine Corps.

I'm a capitalist. I believe in capitalism. But capitalism only works if you have safety nets to deal with people who are naturally left behind and brutalized by it.

I could see America playing a slightly smaller role in the Middle East but I would not see us abandoning the region and just say "Oh," like I said, "China, Russia, it's yours now. Global focus is just on our hemisphere." I don't see that happening.

My mom enlisted in the U.S. Navy in World War II, and my parents actually bought our home thanks to the loan she got through the GI Bill.

If you don't visit the bad neighborhoods, the bad neighborhoods are going to visit you.