First of all, the concept of the separation of church and state, contrary to what people like yourself think, was NEVER included in the Constitution, but, rather, it derived from a misquoted bit of text with absolutely NO legal binding whatsoever, specifically, a letter that one Thomas Jefferson had made to the Danbury Baptists of Danbury, Connecticut.
Nope. The concept of separation of church and state was brought from Europe at the very beginning of the colonization of America--primarily from England--by Christians. Several groups, including the Pilgrims, brought that concept with them.
In England, they were known as "Separatists." The English even fought a civil war over the separation of church and state in the mid 1600s (it was a pretty serious war--the King of England was assassinated, heads rolled). You'll note that was shortly after the Mayflower voyage--the situation in England had been heating up for decades, so some of the Separatists had already gotten to America. Remember, too, that the Thirty Years War between the Holy Roman Empire and the concept of secular nationality only just winding down on the Continent.
So understand that the entire Pilgrim concept was based on separation of church and state, or at least opposition to any single church established as
the church of the kingdom.
One of those Separatists was Roger Williams, an incredibly remarkable man. Roger Williams was a pastor and evangelist who organized the first Baptist congregation in America (Baptists were Separatists).
Besides that, he also learned the languages of the nearby Native tribes and evangelized them. However, he angered other whites because he told the Natives, "Jesus is real, but those people want to steal your land." Williams became a confidant and consultant who was much respected by the Natives.
Williams was also the first American Abolitionist against the slavery that was beginning to be established at that time. Baptists were originally so opposed to slavery that wealthy Baptists didn't even hire domestic servants.
Williams founded the colony of Rhode Island in the late 1630s specifically as a land of total religious freedom. In his writings, Williams explicitly included freedom for "the atheist and the Musselman" (Muslim).
His reasoning is laid out in his treatise "The Bloudy Tenent of Persecution for Cause of Conscience." Because of what Williams saw as both the history and the then-current reality of persecution and war
by Christians
upon Christians, he was convinced that Christ never intended to wield the sword of earthly kings.
He also pointed out that when the earthly king established the church, it became socially advantageous (if not required) to join the church. When church membership is a social advantage or requirement, people join for the social advantage (or to escape punishment), not by faith. Moreover, because "
the way is narrow and few find it," then the majority of those in the pews and in church leadership will actually be those who have joined only for its social advantage, so the church is weakened and turned to evil.
On top of that, Williams realized that in a fallen world, earthly governments unavoidably committed evil in order to maintain their wealth and power. Tying the church to that government soiled the church by those evil acts of worldly governments. The church became nothing more than the chaplain on a cruise ship, with no control over directing the ship, but getting called to pray when the sea got rough.
So Williams wrote in "The Bloudy Tenent of Persecution for Cause of Conscience" that there must be a certain "hedge of separation between the garden of the Church and the wilderness of the world." There were certain areas where the state must have civil control in order to maintain order, but the church should not allow the state any role in directing issues of conscience.
Williams' state of Rhode Island was so committed to the concept of separation of church and state that the state blocked ratification of the Constitution until the First Amendment (guaranteeing freedom of religion) was written and ratified first.
And the concept of separation of church and state still exists clearly worded in the latest official Baptist "Faith and Message" document.
In 1801, the Danbury Baptist Association in Connecticut ent a letter, dated October 7, 1801, to the newly elected President Jefferson with concern over the lack in their state constitution of explicit protection of religious liberty, and against a government establishment of religion. The Baptists wanted that protection. Jefferson cribbed the words of Roger Williams, their own denominational founder, when he wrote of a "wall of separation between Church and State."
So, no, you're wrong that the concept of separation of church and state in America originated with Jefferson's letter.