Well, a couple of things.  True devil worship is essentially a myth.  Celebrities sometimes say they do in order to get media attention, there is no serious devil worship in the United States.  And, in 1974, while "parapsychologists" certainly hoped otherwise, ESP was indeed considered supernatural (and fictional) by pretty much everyone else.

Still, this is an Omen-esque plot, two years before "The Omen."  But Michael (as opposed to Damien) never ended up being elected President.  Supernatural thriller, demon spawn.