Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.

At the time the Bill of Rights was passed, there were several states that had state-sponsored religions. I believe Maryland was Catholic, and there were a couple others. By the early 1800's, though, all states had dis-established any state religion, and then the 14th ammendment was passed which essentially imposed Federal restrictions upon lesser governing bodies.

But to jump from there to saying government can have nothing to do with any religious symbolism or information anywhere is rather stupid; after all, even PBS (somewhat, if not as much as may have been in the past, supported by the government) delivers documentaries about religions and there are other things various governmental bodies give grants and other support to that often contain some sort of religious references. For crying out loud, it makes no sense to study Western civilization without also studying the religion(s) associated with it even in a publically funded school.

I tend to agree with the premise that schools should teach science scientifically and not try to teach the psychobabble that the Genesis literalists would like to teach. But neither should it avoid religion with a ten foot pole with this asinine "firewall" concept.