Barack Obama: “Those around him have to understand that violence that they perpetrate against innocent civilians will be monitored and…”

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

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.

A drift towards extremism was "not inevitable