Right at the beginning of the American Revolutionary War, the Patriots made freedom of religion one of their goals. Consider this excerpt from Common Sense by Thomas Paine.
As to religion, I hold it to be the indispensible duty of all government, to protect all conscientious professors thereof, and I know of no other business which government hath to do therewith. Let a man throw aside that narrowness of soul, that selfishness of principle, which the niggards of all professions are so unwilling to part with, and he will be at once delivered of his fears on that head. Suspicion is the companion of mean souls, and the bane of all good society. For myself, I fully and conscientiously believe, that it is the will of the Almighty, that there should be diversity of religious opinions among us: It affords a larger field for our Christian kindness. Were we all of one way of thinking, our religious dispositions would want matter for probation; and on this liberal principle, I look on the various denominations among us, to be like children of the same family, differing only, in what is called, their Christian names.