In an article on the recent ruling against "intelligent design", one of the supporters of ID said, "The founders of this country would be astonished at the thought that this simple curriculum change established religion in violation of the Constitution that they drafted."
Let's try and resolve this business about what would astonish the founders.
Let's start with the basics. You often hear "this country was founded on the principals of Christianity". It wasn't. It was founded on the philosophy of the Enlightenment. This was a time period when people were challenging the established religious and political hierarchy. The founding fathers were, for the most part, Deists. They believed in what's called the Clockmaker theory, which is that some supreme being created the world using complex but discoverable scientific laws, and then left his creation alone to work on its own accord. This is hardly Christianity. Check out this site for an explanation of Deism, and this page in particular for some quotes from the founding fathers on religion.
So the fundamentalists have it wrong. "Separation of Chuch and State" was very much on our founders minds, and teaching religion in a science class would have repulsed them. Some of them were in fact scientists, and far from being astonished that religion wouldn't be taught in a science class, this was their intentention.
Now if you want to talk about the original intent of the authors of the constitution, let's talk about the fourteenth amendment and the bizarre notion that corporations are protected as "persons".