From the May 9 edition of CNN's Anderson Cooper 360:
ANDERSON COOPER (HOST): Douglas, how do you see this, I mean, as a presidential historian?
DOUGLAS BRINKLEY: Well, it's a very troubling abuse of power. Donald Trump just behaved like a tyrant, we see that in other countries in the world, we don't expect it here. Jeffrey Toobin correctly was point out about the “Saturday Night Massacre” in 1973, when Archibald Cox was fired. What was important about that event though was that we had resignations, two real profiles of courage, Attorney General Elliot Richardson and Deputy Attorney General William Ruckelshaus said this is not okay, we're putting our country above party and they quit. And after that “Saturday Night Massacre,” eventually just like Donald Trump didn't want to talk a lot now, Nixon didn't want to talk aloud. When Nixon did come out of the woodwork he said, that's when he famously said “I'm not a crook.” And public opinion polls started turning. You had a plurality of Americans starting to talk about whether Nixon needed to be impeached or not. So the fact that Donald Trump is trying to exonerate himself is deeply troubling I think, to everybody. And there's, the only historical precedent to it, Anderson, really is that “Saturday Night Massacre.”