Trayvon Martin could have been me 35 years ago.

One of the things we're going to have to discuss and debate is how are we striking this balance between the need to keep the American people safe and our concerns about privacy. Because there are some trade-offs involved. I welcome this debate, and I think it's healthy for our democracy.

A free market was never meant to be a free licence to take whatever you can get, however you can get it.

I don't want to exaggerate; having as many African American men as we've had in the criminal-justice system, and the amount of time it takes for the damage done by that to wash through our society and our communities, the disadvantages born out of kids being undiagnosed with mental-health problems early, or not getting the kind of exposure to reading and math when they're 4 or 5 or 6 years old, that carries a cost.

I need you to go out and talk to your friends and talk to your neighbors. I want you to talk to them whether they are independent or whether they are Republican. I want you to argue with them and get in their face.

We've got to make sure that we rebuild the infrastructure in America, because we used to be - have the best bridges, the best roads, the best airports. And now, when you go to China or you go to Europe, you see that they are outstripping us in terms of infrastructure. And if we put people back to work, that would be good not only in the short term, but it would also lay the foundation, the framework for long-term economic and job growth.

Part of what's unique about climate change, though, is the nature of some of the opposition to action. It's pretty rare that you'll encounter somebody who says the problem you're trying to solve simply doesn't exist. When President Kennedy set us on a course for the moon, there were a number of people who made a serious case that it wouldn't be worth it; it was going to be too expensive, it was going to be too hard, it would take too long. But nobody ignored the science. I don't remember anybody saying that the moon wasn't there or that it was made of cheese.