Barack Obama: “I understand -- there's some things that I don't understand. I don't understand Iraq. I don't understand why we weren't…”

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.

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

A drift towards extremism was "not inevitable

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.