Do you know what decision that was or have a reference to it? I have a vague recollection of a decision that referenced that, but I can't remember if it was at the state rfederal level. I do remember that the way it was applied was to stop catholics from using their bible and keeping the KJV in the schools. It was really an amazing piece of convuluted logic.
I believe the case referred to was Reynolds v. the United
States,1878 , where the Jefferson letter to the Danbury
Baptists was first introduced.The case then was concerning
Mormon polygamy.And serious questions remain about the
efficacy of using Jeffersons' letter (even the whole-as
done in 1878-as opposed to the mere fragment used by the
charismatic Ku Klux Klansman Hugo Black, 1947)
It concerned polygamy in the (then) Territory of Utah.