“I was alone, with the . . . soon-to-be president. I was talking about matters that touch on the FBI’s core responsibility and that relate to the President-elect personally. And the nature of the person — I was honestly concerned he might lie about the nature of our meeting, and so I thought it really important to document it. That combination of things I’d never experienced before, but it led me to believe ‘I’ve got to write it down, and I’ve got to write it down in a very detailed way.’”