Hope and optimism aren't just attitudes, they are life strategies.

I don't think a monarchy led by 75- and 80-year-old men [Saudi Arabia] in today's modern world is really sustainable.

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.

The philosopher Ludwig Wittgenstein once remarked that if you ask a man how much is two plus two and he tells you five, that is a mistake. But if you ask a man how much is two plus two and he tells you ninety-seven, that is no longer a mistake. The man you are talking to is operating with a wholly different logic from your own.

When you study history and look at every civilization that has grown up and died off, they all leave one remnant: a major sports colosseum at the heart of their capital. Our fate can be different; but only if we start doing things differently.

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

I'm from Minnesota. I'm optimistic. I mean, that's just who I am.