The current New Yorker has a piece by Edmund Morris on Ronald Reagan, which Morris wrote after Reagan's death. Morris wrote a biography of Reagan in which he inserted himself as a character interacting with Reagan -- rather like Boswell writing about his travels with Johnson without having been there.
Morris didn't invent characters for this article, but Mrs. Laquedem and I were both a little put off by the article, for different reasons. Mrs. L. said that Morris wasn't really writing about Reagan; he was writing to show how well he could craft a sentence. (The article does have some graceful sentences.) I noticed something else: Morris started the article by describing his file-card index of facts and quotations about Reagan, and he took every opportunity to write about his large collection of facts -- his research for his Reagan biography. Then he gave examples of Reagan's famous detachment, such as not recognizing his son Michael at Michael's high school graduation. From this and other examples I got the sense that Morris was saying, "I did all this research about Ronald Reagan and at the end of it I still didn't really know the man: he was unknowable."
Maybe the reason, not guessed by Morris, is that to his associates and supporters, Reagan reflected whatever they wanted to see in him, remaining serenely unchanged. He was their mirror; a mirror that showed them no blemishes or dark spots.