The third count that would almost certainly be included in any indictment of Trump was his effort to pressure McGahn to create a false record to hide the fact that Trump had directed him to fire Mueller. Trump’s attorney initially made a request to McGahn’s attorney to deny a New York Times article reporting that Trump ordered him to fire Mueller. When McGahn refused to recant the story, Trump became angry. He told one aide that McGahn was a “lying bastard” and said that if McGahn didn’t write a letter denying the Times’ account, Trump would fire him.
Later, after McGahn refused to comply with Trump’s request, Trump called him to discuss the matter. Trump told McGahn he did not say what McGahn remembered him saying—he hadn’t used the word “fire,” he said. Trump asked why McGahn had told Mueller’s team about his directive to McGahn. McGahn told Trump he had to—their conversations were not protected by attorney-client privilege—and moreover, that he had notes of the conversation. (Trump told McGahn that he “never had a lawyer who took notes.” McGahn memorably retorted that a “real lawyer” does.)
Although asking someone to write a letter is typically not a crime, in this case, McGahn was an important witness against Trump. If McGahn wrote a letter that lied about what Trump did and said, it would completely undercut his value as a witness against Trump.