I got a letter from 13-year-old Ryan from Belfast. Now, Ryan, if you're out in the crowd tonight, here's the answer to your question. No, as far as I know, an alien spacecraft did not crash in Roswell, New Mexico, in 1947. And, Ryan, if the United States Air Force did recover alien bodies, they didn't tell me about it, either, and I want to know.

I know that the precise magnitude and patterns of climate change cannot be fully predicted. But global warming clearly is a growing, long-term threat with profound consequences. And make no mistake about it, it will take decades to reverse.

The great thing about not being president anymore is I can say whatever I want, about anything. Of course [now], nobody really cares what I say. And now I have the worst of all worlds -- my wife has become the secretary of state, so no one really cares what I say -- unless I mess up.

Success is not the measure of a man but a triumph over those who choose to hold him back.

When I first came to Washington in the 1960s, even at the height of the Vietnam War, until the end there in '68 there was a certain climate of cooperation. And then in the late sixties and in through the seventies, politics began getting more mean. And then from the eighties on it seemed to be institutionalized, this personal attack business. And I just hate it.

A world without walls is the only sustainable world. . . . If the world is dominated by people who believe that their races, their religions, their ethnic differences are the most important factors, then a huge number of people will perish in this century.

When you're a former president, you have much less power, but you have a lifetime of experience and contacts and if you've got the energy, you can bring influence to bear on a small but still fairly substantial number of things where you can concentrate on it because you don't have to change the subject when you wake up in the morning and there's something else in the newspaper.