There aren't a lot of situations where I look back and I say, The decision I actually made or the course we actually pursued was the wrong course.

One of the things that you learn, having been in this [President's] office for four years, is the old adage of Abraham Lincoln's. That with public opinion there's nothing you can't do and without public opinion there's very little you can get done.

If you're reading something from a Nobel Prize-winning physicist next to some guy in his underwear writing in his basement, or his mom's basement, on text, it looks like it's equally plausible.

It's hard to anticipate. I can tell you what I'm feeling right now is that I'm busier than I expected these last two weeks. A great deal of emotion around the people that I've worked with and the gratitude I feel for the sacrifices they've made on behalf of the American people, but also on behalf of me personally.

It's time to "stop being ambivalent." ... They (groups like the Islamic State) have no ideology beyond violence and chaos and the slaughter of innocent people.

And I believe the nation that invented the automobile cannot walk away from it.

There are folks who will equivocate. They'll say, 'You know, I'm not a scientist.' Well, I'm not either. But the best scientists in the world know that climate change is happening.