Hmmm. Congress shall make no law regarding an establishment of religion or the free exercise thereof. Not allowing Wiccan convocation does not prevent free exercise. But, it does indicate something akin to aversion. Tough to say where this one will go. It'll probably boil down to not allowing a formal convocation by any religious figure, which has been the response in the past. The trouble with the ACLU is an entrenched anti-establishment attitude that goes back to the founding of that organization by, essentially, communists. Christianity plays a large establishment role in the US, so the ACLU is against it, rather than the other way around, which would be support for Wicca or any other religion that is outside of the establishment. When you get right down to it, the ACLU is antireligion. Some religions are more "revolutionary" than others, and hence more useful. But they'll all be eventually targeted.
> Congress shall make no law regarding an establishment of religion or the free exercise thereof.
True, but did the founders intend that there be the free exercise of cults and paganism? I think we have to draw the line somewhere, and witchcraft belongs on the other side of it.