Obama said if elected his government would "harness technology to confront the biggest challenges that America faces".

So if somebody wants to build a coal-powered plant, they can; it's just that it will bankrupt them because they're going to be charged a huge sum for all that greenhouse gas that's being emitted.

You could analyze me and say that my father leaving and being absent was a motivator for early ambition, trying to prove myself to this apparition who had vanished. You could argue that me being a mixed kid in a place where there weren't a lot of black kids around might have spurred on my ambitions. You could go through a whole litany of things that sparked me wanting to do something important.

We can't get to the $4 trillion in savings that we need by just cutting the 12 percent of the budget that pays for things like medical research and education funding and food inspectors and the weather service. And we can't just do it by making seniors pay more for Medicare.

Even as we implement the nuclear deal and welcome our Americans home, we recognize that there remain about differences between the United States and Iran. We remain steadfast in opposing Iran's destabilizing behavior elsewhere, including its against Israel and our Gulf partners and its support for violent proxies in places like Syria and Yemen.

We may never understand what leads anybody to terrorize their fellow human beings. Such violence, such evil is senseless. It's beyond reason.

America leads - not with bluster, but with persistent, steady resolve.