‘America was a Christian nation.’
actually, America was an Enlightenment nation...the Age of Reason, and all that, acknowledging the abstract deist notion of the Creator, rather than the specific Judeo-Christian God...
Of the 55 men working on the constitution, 52 considered themselves to be evangelical Christians. They envisioned school children praying in class as well as teachers using the Bible for educational purposes.
When Thomas Jefferson was made president of the Washington, DC, public school system he placed the Bible and Isaac Watt's hymnal as the two primary reading texts! This is why Biblical morality was taught in public schools until the early 1960's.
Government officials were required to declare their belief in God even to be allowed to hold a public office until Oct. 1960. God was seen as the author of natural law and morality. If one did not believe in God one could not operate from a proper moral base. And by not having a foundation from which to work, one would destroy the community.
So firm were they in their resolve that the same day Congress passed the first amendment (Sept. 25, 1789), they also approved a resolution requesting President George Washington to proclaim "...a day of public thanksgiving and prayer...."
America considered itself to be a Christian nation. Read your history. Even when we moved the American Indian to the reservations it was to evangelize them. Historically.