Every time I’ve seen a thoughtful mention of the separation of church and state, it has emphasized the harm that the church can do to the state. And the Founding Fathers, flawed as they were, at least did not suffer from the amnesia that modern Evangelicals and the Republican Party do.
They remembered the many religious wars that began in 1553 when Henry VIII broke with Rome and established the Church of England out of whole cloth. The battles continued, on and off, through the Scottish Reformation, the English Civil War, the war in Ireland that exiled or killed 30% of the natives, and only ended with the exile of Scotland’s Bonny Prince Charlie in 1745. They also remembered the repeated religious wars in France, the Thirty Years War in Germany, and the two Kappel Wars in Switzerland. In fact, religious wars riled Europe for 150 years.
That’s a lot of bloodshed.