 Supreme Court ever used the phrase, the separation of church and state. And that's an amazing thing when you think about it. If this was such a foundational doctrine of our country, why did the Supreme Court never mention it for 150 years? It wasn't until 1947, the case of Everson versus the Board of Education. This was a case in which the state of New Jersey was using tax dollars to support religious schools. Back then, the only religious schools were Catholic schools.