It could be another election where the alignments between Republicans and Democrats are different than they were this time and who a foreign country prefers.

I've always viewed the Paris Agreement as a starting point. If you look at all the commitments that have been made by all the countries, it's still not sufficient to deal with the very dangerous situation we face. What it has done is that it created an architecture whereby as technology improves, as we find new clean sources of energy, as we make our economies more efficient, then gradually we can turn up the dial and improve the outcomes of Paris.

And to those nations like ours that enjoy relative plenty, we say we can no longer afford indifference to the suffering outside our borders; nor can we consume the world's resources without regard to effect. For the world has changed, and we must change with it.

Too many Americans who struggle with mental health illnesses are suffering in silence rather than seeking help, and we need to see to it that men and women who would never hesitate to go see a doctor if they had a broken arm or came down with the flu, that they have that same attitude when it comes to their mental health.

Without a deal [with Iran], the international sanctions regime will unravel with little ability to reimpose them. With this deal, we have the possibility of peacefully resolving a major threat to regional and international security. Without a deal, we risk even more war in the Middle East and other countries in the region would feel compelled to pursue their own nuclear programs, threatening a nuclear arms race in the most volatile region in the world.

What we have done, I think, is build a model from a lot of hard lessons in Afghanistan and Iraq but in other places around the world, where we are working with them in an advisory capacity.

[About his marijuana use] I did. It's not something that I'm proud of. It was a mistake as a young man, but you know? I mean not going to -- I never understood that line. The point was to inhale. That was the point.