The separation of church and state is really what made this country great.
In 1777, Thomas Jefferson drafted a bill to the House of Delegates of Virginia called "the Statute of Virginia for Religious Freedom." This bill was adopted by the Virginian legislature in 1786 after years of effort with James Madison's help. It was a bill that went beyond John Locke's policy of toleration and enacted complete religious freedom not only of all Christian groups but of all religious opinions whatsoever, including, in Jefferson's words, "the Jew, the Mahometan, and the Hindoo." One of the following reasons why he argued for religious freedom was because the "Almighty God hath created the mind free" and "free it shall remain." He spoke out against enforcing religious uniformity by "temporal punishments" or "civil incapacitations" because it was doomed to failure. He believed it was against God's plan through the influence of reason. He believed it was "sinful and tyrannical" to force a man or a woman to support a religion "which he disbelieves and abhors." He believed it was as foolish to penalize a citizen for his religious opinions as for his ideas of science or education depriving him of his "natural right." He thought the religious establishment was bad when it is combined with the federal or state government. A church was a "voluntary society," and a person "should be se free to go out as he was to come in."
In 1787, the Founding Fathers met in Philadelphia for a constitutional convention.
They drafted a written constitution for the people of the USA. In that Constitution, there is only one specific use of the word religion and it is in Article 6, Section 3.
It states that all senators, representatives, members of state legislatures, all executive and judicial officers, both federal and state shall be bound by oath or affirmation to support the Constitution. It also says "no religious test shall ever be required as a qualification to any office or public trust under the United States."
Lastly, Alexis de Tocqueville believed the people's fervor for God in the churches was what made America great. It was our religious freedom that made us great and he discovered that the clergy and the laity "all contributed the peaceful dominion of religion in their country mainly to the separation of church and state."