I want to know the answer to the following question:
When was the centrality of the "separation" concept to the Religion Clauses of the Constitution made explicit?
All the background I'm provided with is that "This was the first case in which the court applied the Establishment Clause to the laws of a state, having interpreted the due process clause of the Fourteenth Amendment as applying the Bill of Rights to the states as well as the federal legislature.". Is that enough to answer the question?
Answer: no