David Gergen: “I do think the president has got some tough calls to make.”

I think the turning point that came were the midterm elections. The fever broke with those midterm elections. And what we've seen since then is a steady decline in Trump's credibility and in his position with the American people, and a…

If he had a receptive audience, and I will tell you, when everything -- when all the facts were to come out, it would be like Nixon and the tapes.

It's very, very big. Not legally, but politically, it's a very, very big deal.

The midterms really helped him. They transformed the race, best midterm elections for any president in 20 years.