Barack Obama: “I often say that John McCain is running to serve out George Bush's third term. But that's not fair to George Bush.”

It is a decision about how do we face and embrace this finite amount of time we have on the planet.

If I had a blame pie for why politics is so polarised and why we're seeing a rise of populism in many places, it's because of that information that is going into our brains every day.

When we choose, when we make that decision, I do believe – and there is evidence for this – that the world gets incrementally better, and that is a worthy goal and it’s worth fighting for.

And I will fight for that, even if I don’t always think it’s going to win.