Writing has been an important exercise to clarify what I believe, what I see, what I care about, what my deepest values are. The process of converting a jumble of thoughts into coherent sentences makes you ask tougher questions.

The trick is figuring out how do we structure government systems that pool resources, and hence facilitate some [wealth] redistribution, because I actually believe in redistribution, at least at a certain level, to make sure that everybody's got a shot.

If we're going to prevent large parts of this Earth from becoming not only inhospitable but uninhabitable in our lifetimes, we're going to have to keep some fossil fuels in the ground rather than burn them and release more dangerous pollution into the sky.

We have reaffirmed again and again that the United States is not and never will be at war with Islam. Islam teaches peace, and when it comes to America and Islam, there is no us and them, there's only us, because millions of Muslim Americans are part of the fabric of our country. So, we reject any suggestion of a clash of civilizations.

If you look at the current Mosul campaign against ISIL, for example the few thousand troops that we have there to support that effort allows the Iraqi military to move forward in an effective way.

Degrade and ultimately destroy ISIL

I'm blown away. I'm flabbergasted the president [Barack Obama] made the phone call to Rouhani after 30-plus, `79, 33 years or so. And there's a reason we haven't negotiated with Iran, because they're state-sponsored terrorists. They're the central bank for terrorism around the world.