Barack Obama: “We've made enormous progress, but those letters tell me that we haven't made enough.”

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.

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

A drift towards extremism was "not inevitable

I think when we act on that basis, it doesn't always work out, but over time things do get better.