Anyways, the fun thing about St. John's case on appeal is that it might be one of those briefs which involves a whole lot of incredibly obscure legal research.
We know magic exists and is a big deal in Marvel (in general). We know that these magicians existed and were active hundreds of years ago. And we know that even in the real world there were a lot of things like witch trials and stuff. So it wouldn't be the strangest leap of logic for a lawyer to go "well, 17th century court cases from England discussing the plight of men and women gifted with mysterious and exceptional powers that defy scientific understanding might be usable in a 20th century court to explain how the court should address 20th century men and women gifted with mysterious and exceptional powers" and Antonin Scalia immediately pops a boner and doesn't know why.
I wouldn't be surprised if there were precedents people could pick from extremely obscure 17th century law that would have covered similar situations, although I suspect that perhaps Witchcraft Law is not very favorable to a mutant defendant even ignoring the connotations, so it's probably going to be the prosecutor's office gleefully citing 17th century precedent.