The Jeffersonian Ideal of Church-State Separation

There is no such thing. 

The Jeffersonian ideal was to separate the federal government from any particular Christian denomination - that is not not have an established church like the Church of England in 'England and Wales'. 

It did not proscribe a broad, civil, non-dogmatic, cultural Christianity as the moral bedrock and the least common denominator of economic and political life. (Tangentially, nor did Jefferson explicitly refer to established churches in the constituent states, although he was averse to that too.) 

Coming back to cultural Christianity, I do not share C.S.Lewis' objection to it as a watered-down religion that must be relegated to the trash bin.. You see, cultural Christianity beats cultural secularism as our 'political religion' any day. Yes, we should separate particular forms of Christian dogma and praxis from political life, but the USA is a Christian nation and it is is perverse misinterpretation of the constitution to divorce our politics from a broad Christianity, or to use the IRS to ban political discourse from the pulpits. 

Jefferson was a Deist but a Deist within a profoundly Christian culture, one who created his own bowdlerized New Testament whose value we can certainly dispute but whose Christian orientation we can in no wise deny. 

In other words, let our churches practice particular forms of Christianity and let not the federal or state governments interfere with that. But let us also acknowledge a least-common-denominator Christian culture as the bedrock of our civil life in lieu of the humanist, secular value system that has usurped its place. 

And let Jews and Buddhists and Hindus and Shamanists and Baha'is and Zoroastrians and UUs and Jains and Wiccans and Sikhs and Shintoists and Daoists and Agnostics and Athesits and Sufis and Animists be welcome in our midst by Christian sufferance, and not as itsy-bitsy tails that wag the dog.

The USA for the Lord Jesus Christ !!