John Dean: My appearance before Congress helped take down Nixon. Will the same thing happen to Trump?
John Dean writes: There is one overarching similarity that Mr. Cohen and I share. He came to understand and reject Mr. Trump as I did Mr. Nixon. Mr. Nixon first called on me regarding Watergate some eight months after the arrests of his re-election committee operatives at the Watergate. We had 37 conversations, and when I felt I had his confidence, I tried but failed to get him to end the cover-up. The day I told Mr. Nixon there was…