Today we're seeing that climate change is about more than a few unseasonably mild winters or hot summers. It's about the chain of natural catastrophes and devastating weather patterns that global warming is beginning to set off around the world.. the frequency and intensity of which are breaking records thousands of years old.

The second thing we have to do is to make sure that all of us think about how we approach our elections and our democracy not only to secure them from vote tampering, but also to make sure that we understand when propaganda is being churned through the system.

Losing the PR battles, particularly about healthcare, translated into losing his Democratic majorities in Congress, beginning with a Republican landslide in the midterm election of 2010.

If 90 percent or 95 percent of those - chemical stockpiles [in Syria] were eliminated, that's a lot of chemical weapons that are not right now in the hands of ISIL or Nusra or, for that matter, the regime.

When I turn over the keys to the president-elect, America will be much stronger than it was when I came into office.

As I got older, then my particular ambitions started cohering around creating a world in which people of different races or backgrounds or faiths can recognize each other's humanity, or creating a world in which every kid, regardless of their background, can strive and achieve and fulfill their potential.

Cuba is actually one where I am more optimistic because of the unique nature of Cuba - 90 miles off our shore with a massive ex-patriot population, now Cuban-American population that still have deep links to the island. There I am more confident that over time that the winds of commerce and telecommunication and travel start shifting the nature of that regime. But that's a small country which has almost a unique relationship to us.