Other Tink found a fascinating YouTube video, a PBS Frontline documentary on the history of religious freedom in the USA. The Baptists wanted their right to preach and evangelize along with the established state religion in Virginia, so they went to Thomas Jefferson.
Well, Jefferson disagreed with the Baptists on virtually everything, but he believed they had the right to have their say. So he became their champion and introduced a bill into Congress, and it passed!
Then in the 1800's, a Catholic bishop advocated for the right of his parishioners to attend public school in New York without Protestant propaganda. The city council voted him down, so he went through the political process, asking his parishioners to vote for the liberal candidates...and so when those candidates won, laws were enacted taking Protestantism out of the schools! This was quite an event, because the USA was founded on principles of the Protestant Reformation and the Age of Reason.
The separation of church and State was thus incorporated into shaping America's identity...and that had never really been done before...do we still have that freedom? (I DO think so, hope so...we have not lost that one yet.)