The Declaration was a statement to King George.  It has no legal standing or influence on governing this country.  In the Declaration was the famous phrase that "all men are created equal.  And they really were referring to MEN.  White men.  Women, slaves, indigenous tribes and people without property need not be considered for equality.  

As for the founders, most were Deists.  Like the politicians of today they threw around religious phrases and terms, but their private writings revealed their true feelings--a desire for a secular state. There is no official US government document, legally binding that establishes the United States as a Christian nation.  There are official documents that clearly state the opposite.  

Mr. Kaminski, in his letter, referred to  the Constitution.  Find clear references to Christian values in the Constitution.  

I'll wait.