Barack Obama: “The United States strongly condemns the barbaric murder of U.K. citizen David Haines by the terrorist group ISIL.”

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.

It is a basic principle of American democracy that the government can’t selectively target individuals simply because of their political beliefs or what they say.

A drift towards extremism was "not inevitable