Most people that I have heard refer to the US as a Christian nation mean that it was founded by Christians and upon Christian values. I would not doubt that they believe that there is distinct language to that effect in the founding documents because the phrase "Christian nation" in that context would imply it. Those are usually the same people who want the ten commandments plastered on every wall and creation taught as a science and gays and illegals catapulted into Mexico (or the Pacific Ocean).
"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape- like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered."
-Stephen Jay Gould
-Stephen Jay Gould
