Barack Obama: “It is too fragile, and it is too important for us to be able to endanger it in any sort of way.”

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.

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

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