I don't know, but whoever it was is a moron. If Kim's button is big enough to destroy the US, it really doesn't matter if that other person has an even larger button.
We currently have 5 times the amount of nuclear weapons we need to end life on earth, without even launching them. Blowing them up in their silos is good enough. So why are we building new weapons? 5 times isn't enough, we need an even larger button? No, that person is a moron; whoever he is.