Susan Rice: “You know, we have in Donald Trump a leader who is not running to be the president of the American people. He's running…”

But this summit meeting really ought to be tackling the toughest issues facing the world today, top of the list being the grave risks posed by rapidly accelerating artificial intelligence, as well as what's going on in Ukraine, what's…

I have never heard of something like that.

I do believe he would do it. I believe we have -- if we have learned anything, we should listen to what he says and what he does is often exactly what he says and sometimes worse.

When the people closest to you say you're unfit to lead, that's very, very concerning and dangerous.