I would have I think made a bigger mistake if I had said, "Eh, chemical weapons. That doesn't really change my calculus." I think it was important for me as president of the United States to send a message that in fact there is something different about chemical weapons [in Syria].

We may never understand what leads anybody to terrorize their fellow human beings. Such violence, such evil is senseless. It's beyond reason.

In the Muslim world, this notion that somehow everything is the fault of the Israelis lacks balance - because there's two sides to every question. That doesn't mean that sometimes one side has done something wrong and should not be condemned. But it does mean there's always two sides to an issue. I say the same thing to my Jewish friends, which is you have to see the perspective of the Palestinians. Learning to stand in somebody else's shoes to see through their eyes, that's how peace begins. And it's up to you to make that happen.

If it's on Facebook, it all looks the same.

Each side has legitimate aspirations - and that's part of what makes peace so hard. And the deadlock will only be broken when each side learns to stand in the other's shoes; each side can see the world through the other's eyes. That's what we should be encouraging. That's what we should be promoting.

I actually believe that we need missile defense, because of Iran and North Korea and the potential for them to obtain or to launch nuclear weapons, but I also believe that, when we are only spending a few hundred million dollars on nuclear proliferation, then we're making a mistake.

I think it's fair to say that [Donald Trump] and I are sort of opposites in some ways.