There have been times where, let's say on LGBT issues, when we were trying to end Don't Ask, Don't Tell, and I got the Pentagon and Bob Gates, a Republican holdover from the [George W.] Bush administration, to authorize a study of how you might end Don't Ask, Don't Tell, headed up by Jeh Johnson, who at that time was a council to the Justice Department. And it was going to take a year to conduct that study, issue a report, and figure out how it might be implemented, what effect it would have on unit cohesion and military effectiveness.

There is a word in South Africa - Ubuntu - that describes his greatest gift: his recognition that we are all bound together in ways that can be invisible to the eye; that there is a oneness to humanity; that we achieve ourselves by sharing ourselves with others, and caring for those around us.

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.

The reason I take pride for that is one of the things you worry about when you're in the bubble, and there's all this pomp and circumstance and hail to the chief is, do you lose touch with what you thought was important and what brought you here? And I'm proud that I don't think I have lost touch.

Certainly I've appreciated Angela Merkel as a partner.

Together we resolve that a great nation must care for the vulnerable and protect its people from life's worst hazards and misfortune.

Few challenges facing America and the world are more urgent than combating climate change. The science is beyond dispute and the facts are clear.