Or any of the founding documents. It comes from a private letter Jefferson wrote to the Danbury Baptist Church in 1801.
They were talking over each other and she was talking about her opponent’s use of that particular phrase, not the “establishment clause.”
That the law school audience “gasped” demonstrates their own ignorance, not her’s.
And it’s “Congress shall make no law…” not “Government…”
I’m a lowly Canadian, and I know this.