the fact that Freud linked the two things together, the very title of the book shows the evil th that group psychology and ego psychology were intimately  intimately connected with one another and er the central idea was that as Dean rightly says is that in a group the leader or the leading principal, and it doesn't always have to be a person, although usually a person plays, kind of represents the, the er  the leader in the way that the Pope represents Christ for example, you know Christ can't be here right now, he's doing other things elsewhere I presume.