The nut who does the shooting is always the front man. Every time.
Who put the nut up to it and why? Those are the important questions.
It was always thought that the Mafia had put Zangara up to killing Roosevelt due to the fact that they were making so much money due to prohibition. But there are also those who have wondered if Mayor Cermak, who was giving the Mafia a very hard time in Chicago, could have been the actual target.