Over the years since I have become an atheist I have written on this subject before: The claim by the Christian faithful that this nation was meant to be a “Christian Nation” and that the founding fathers meant it to be so. To that I say “Nah”.
If you consider the many quotations in the support of the separation of church and state that were made by the founding fathers at the time a realization of the true intent is clear.
The Government of the United States of America is not in any sense founded on the Christian religion. – 1797 Treaty of Tripoli signed by John Adams.
I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should make no law respecting an establishment of religion, or prohibit the free exercise thereof, thus building a wall of separation between church and state. – Thomas Jefferson, letter to the Baptists of Danbury, Connecticut, 1802
Christianity neither is, nor ever was a part of the common law. – Thomas Jefferson, letter to Dr. Thomas Cooper, February 10, 1814
The civil government functions with complete success by the total separation of the Church and State. – James Madison, 1819.
Strongly guarded as is the separation between Religion and Government in the Constitution of the United States, the danger of encroachment by Ecclesiastical Bodies, may be illustrated by precedents already furnished in their short history. – James Madison.
No religious doctrine shall be established by law. – Elbridge Gerry.
There are many more quotes that indicate the direction that the founding fathers intended for the nation. Some can be found here: addictinginfo.