The most conclusive evidence that this is not a Christian nation comes from the US Constitution itself. The document that our government and laws are based on. Nowhere in it is there any mention of God, Jesus, Christianity, or any other religion. In fact, religion is mentioned only twice: In the 1st amendment it says, "Congress shall make no law respecting an establishment of religion or prohibiting the free exercise thereof," which Thomas Jefferson interpreted in his letter to the Danbury Baptist Association of 1 January 1802:
"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 prohibiting the free exercise thereof,' thus building a wall of separation between church and State."While it is true that "separation of church and state" is not explicitly mentioned neither is "freedom of religion," and yet, both are implied by the 1st amendment. The other place where religion is mentioned is in Article VI, Section 3, ". . . no religious test shall ever be required as a qualification to any office or public trust under the United States."
There is also much evidence for the secular nature of the US government to be found in the words of the founding fathers themselves. So Happy Birthday USA, one Nation, Indivisible, with liberty and justice for ALL.