What if we're wrong and there is no climate change? Well, by doing everything possible to address it, we will still use less water, stimulate new energy savings and, in time, money-saving technologies, enjoy cleaner air, and preserve more forests and trees and animals.

That's right-the striking thing about greenhouse gases is the diversity of sources that emit them. A herd of cattle belching can be worse than highway full of hummers.

Our bailout of Detroit will be remembered as the equivalent of pouring billions of taxpayers' money into the mail-order catalogue business on the eve of the birth of eBay.

There is definitely global warming, and man is definitely contributing to it. Go out to, say, Montana and talk to some pretty conservative people, hunters and fishermen. They know that in the trout stream they fished when they were growing up, the trout are stressed because the water temperature is going up. They know the hunting season has been delayed because the snows are coming later, and therefore the elk aren't coming down from the mountains.

There's a difference between being able to make long distance phone calls cheaper on the Internet and walking around Riyadh with a PDA where you can have all of Google in your pocket. It's a difference in degree that's so enormous it becomes a difference in kind.

The Arab world had a big problem of frankly venal elites. That is why these revolutions happen, because people didn't think the opportunities were being shared fairly.

Geopolitics is all about leverage. We cannot make ourselves safer abroad unless we change our behavior at home.