AMERICA FOUNDED AS A CHRISTIAN NATION? YES!
Both federal and state courts ruled on that until much later. Whatever happened later cannot over rule the believes of the founding fathers through whom those who changed the law were given life.

1. Church of the Holy Trinity v. United States, THE UNITED STATES SUPREME COURT, 143 U.S. 457, 12 S.Ct. 511, 36 L.Ed. 226 (1892):


"Our laws and our institutions must necessarily be based upon and embody the teachings of The Redeemer of mankind. It's impossible that it should be otherwise; and in this sense and to this extent our civilization and our institutions are emphatically Christian... This is a religious people. This is historically true. From the discovery of this continent to the present hour, there is a single voice making this affirmation... we find everywhere a clear recognition of the same truth... These, and many other matters which might be noticed, add a volume of unofficial declarations to the mass of organic utterances that this is a Christian nation."

Read other related court rulings and Joint US Congress declaration here:
http://house-era.com/index.php?topic=646.msg1098#msg1098