In the film "Arsenic and Old Lace" which president does the crazy middle brother believe himself to be?

It was a Broadway play before it was a movie. In the play, the part of crazy, murdering Jonathan was played by Boris Karloff. There are several lines about Jonathan’s new plastic-surgery face resembling Karloff or someone seen in a horror movie. Unfortunately, when the movie was made, the play was still running on Broadway and the producers refused to release Karloff for the film. What is a very funny movie would have been even funnier.

One of my all-time favorite movies. Carrie Grant is fabulous.