A real interesting essay would be how this whole separation of church & state was implemented by the Supreme Court, the players involved, how they got away with this and why?
There is some merit to separation being a concern of the Founding era. The history of the English Civil War of the 1600s was well known to the American colonists - warring factions had included Anglican Arminians, English Calvinists, Scots Irish Presbyterians, and Irish Catholics. A lot of the American colonial population were descended from religious groups who set sail as a result of that Civil War.
The New England colonies were hostile to non-Congregationalists. Virginia had the Church of England as its State Church. Dissenting groups, Baptists, Methodists, and so forth were very wary of having a new State Church establish itself after the Revolution.
"Separation of church and State" by Philip Hamburger, (Law Professor at the University of Chicago)University of Harvard Press ,2000; see also "thomas Jefferson and the Wall of Separation between church and State" by Daniel Dreisbach ,New York University Press,2000;See also Library of Congress display "Christianity and the Founding of the
American Republic,1998James H.Hutson-to name a few,