The Founders drew on the Bible and believed that Christianity was necessary for civil morality in a republican system.

It doesn't follow, however, that they believed Christianity should be imposed through law. The First Amendment is very clear - indeed, is even clearer in its first draft. Government shall make no laws respecting the establishment of religion.

Yes, freedom of religion doesn't mean freedom from religion. No one is arguing that it means that. But it does mean that government will not impose religion through law, including through laws governing public school.

Why is this important? For one reason, a reason that all Christians can accept, it prevents one sect of Christianity from gaining dominance over any others. It's easy for Christians to say that America should make laws based on the Bible against atheists or Muslims. But let's say we do: which Christianity do we use? Baptist? Unitarian? Catholic? "Nondenominational"? Calvinist? Lutheran? Should schools teach that Christ was a human, a god, or both man and God? Should schools teach pre-trib or post-trib? Etc.

Now part of the confusion here arises from the fact that the Bible used to be taught in schools. But the schools in which it was taught were state-run schools. States weren't originally bound to the Constitution, and so if their state constitution permitting teaching the Bible, they could do so. But with the steady imposition of the federal constitution on the states, the first amendment has come to apply within the states. Furthermore, the federalization of schools and required the imposition of the first amendment on state schools. So while state schools could teach the bible previously, they find it increasingly hard to do so now.

The answer is obvious: free up the education system, and then the freedom of atheists like myself is respected (my children won't be forced to learned Christianity at the point of government's gun), and Christians will be free to teach their children whatever brand of Christianity they prefer.