Today, about 40 percent of America's carbon pollution comes from our power plants. There are no federal limits to the amount those plants can pump into the air. None. We limit the amount of toxic chemicals like mercury, and sulfur, and arsenic in our air and water, but power plants can dump as much carbon pollution into our atmosphere as they want. It's not smart, it's not right, it's not safe, and I determined it needs to stop.

I think part of the reason that I have been successful, though, despite maybe not always fitting my message into the pre-packaged formulas, is there is this whole other media ecology out there of the Internet and Instagram and memes and talk shows and comedy, and I'm pretty good at that.

The leaders we revere and the businesses that last are generally not the result of a narrow pursuit of popularity or personal advancement, but of devotion to some bigger purpose. That's the hallmark of real success. The other trapping of success might be the by product of this larger mission, but it can't be the central thing.

In our household, the Bible, the Koran and the Bhagavad Gita sat on the shelf alongside books of Greek and Norse and African mythology

This is the defining issue of our time. This is a make-or-break moment for the middle class and for all those who are fighting to get into the middle class.

What I remember thinking at that point, having gone through both the ups and downs of my first four years, and seeing the sea of people was, "What a remarkable country this is and how lucky am I that we live in a place where the son of a single mom, not born into any kind of fame or fortune, in a pretty remote state somehow can end up be in a position to - to make a difference."

We must begin by acknowledging a hard truth. We will not eradicate violent conflict in our lifetimes. There will be times when nations, acting individually or in concert, will find the use of force not only necessary but morally justified.