No Harry Hopkins?

My impression was that, at least in the White House, FDR and Hopkins were virtually inseparable. Thus, when I saw Hume Cronyn's name in the cast, I assumed he played Hopkins. Joining the movie an hour in, however, I heard the cast referring to the Cronyn character as "Louie." Thus I assumed he was Louis Frankfurter. Not so. Louis Howe.

Then, when I reviewed the cast on IMDB, I discovered to my surprise that the movie contains nothing of Harry Hopkins. Somewhat of a surprise.