Which forefathers are you talking about? If you mean the pilgrims this is not correct. Both they and the English before them attempted to convert the natives to Christianity.
Discussion
was that a good thing in your opinion?
Not necessarily. The carrot is almost always better than the stick.
Some context:
The declaration of independence is literally an appeal to God.
Separation of church and state is the govt staying out of the church's business not the other way around.
While it is not and has never been a requirement to be Christian, the underlying values written into the original constitution and it's early amendments are clearly Christian values.
