I'm honestly surprised that this thread is still open today. While I spied on it at work (where posting here, I bet, would probably get me fired in the long run), I found myself interested in commenting on a few things here.
First off, I don't think that we're all operating on the same set of terminology. "Creationism" can mean "young-Earth creationism," where the Earth was created over a literal seven, 24-hour days and the universe is approximately 6,000 years old. The Creation Museum, apparently, prescribes to an extremist form of this theology. This is the kind of creationism that people who are opposed to it automatically start visualizing in their heads, because it is the most unscientific and disproven of them of all.
Then there's some who use the term "creationism" to mean "intelligent design," which is a fundamentalist Christian-constructed theology that mixes a semblance of science with a rather haphazard and subjective appliance of religion to create something that honestly resembles nothing of either.
This theology exploits the general public's lack of deeper science education, because, as Irvine511 pointed out yesterday, there is a huge difference between the vernacular definition of "theory," which is essentially conjecture, and the scientific definition of "theory," which is the end result of years of study and peer-reviewed documentation. Gravity is technically defined under a scientific "theory," not a "law," and the Theory of Gravity has been heavily amended over the years, because of advances in scientific understanding and knowledge.
As such, "intelligent design" is not scientific, by nature of the fact that it has not passed the level of experimentation and peer review that an actual scientific theory would have to undergo to receive that status. By definition, though, ID will never receive that status, because it infuses the untestable and unverifiable notion of "God" in it. ID is, nothing more and nothing less, bad theology and terrible science.
The third alternative, which is highly prevalent, but probably the least recognizable by name, is "evolutionary creationism," a.k.a., "theistic evolution." In short, those who believe this accept the entirety of science in regards to evolution, but attribute it to God. So, basically, the Big Bang? Created by God. A 13 billion year old universe? Created by God. Science discovers that the universe is really 20 billion years old? We just didn't measure God's creation accurately. Natural selection? A part of God's plan that we cannot comprehend. And, indeed, although atheist scientists like Richard Dawkins get all the media attention, there have been theists all throughout the history of the theory of evolution. Alfred Russel Wallace, a contemporary of Charles Darwin who also made many contributions to evolution by natural selection, was strongly spiritual.
Theodosius Dobzhansky, a Russian Orthodox Christian and an evolutionary biologist, wrote this famous quote in 1973:
"I am a creationist and an evolutionist. Evolution is God's, or Nature's, method of creation. Creation is not an event that happened in 4004 BC; it is a process that began some 10 billion years ago and is still under way... Does the evolutionary doctrine clash with religious faith? It does not. It is a blunder to mistake the Holy Scriptures for elementary textbooks of astronomy, geology, biology, and anthropology. Only if symbols are construed to mean what they are not intended to mean can there arise imaginary, insoluble conflicts... the blunder leads to blasphemy: the Creator is accused of systematic deceitfulness."
I, myself, believe in the last concept of "evolutionary creationism." Conflict between science and religion today is increasingly pointless in light of this concept, and that's why threads like these today, over 140 years after Darwin's original paper on evolution, are downright silly.
Now as for whether to teach God in science class, I'm reminded of a Bible verse:
"There is an appointed time for everything, and a time for every affair under the heavens." - Ecclesiastes 3:1
Science class is the time for science, and religious studies, whether in a private Christian school, in Sunday school, or in a church sermon, are the time for religion. To mix religion into science would degrade science, just as mixing numerology would degrade mathematics. To those who don't accept the scientific theories on evolution, you don't have to accept them--that is your constitutional prerogative--but you would be doing yourself a great disservice not to understand it, just as one would take a comparative religion class to understand the various religions of the world.
As for the place of secularism in this world and the American Founding Fathers, it must be remembered that Christianity then and Christianity today were vastly different. Evangelical and fundamentalist Christianity did not
exist until the 1830s, but they were the ones that propagated the oft-quoted fallacy that our Founding Fathers were devout Christians, which they used as a tool for evangelism. The reasoning was that by propping up our Founding Fathers as "Christian heroes" worthy of emulation, people would strive to be like them. Needless to say, it worked, but that does make it any less fallacious.
Our Founding Fathers were Enlightenment-era deists, whose modern equivalent would be Unitarians or agnostics. It has to be understood that Americans were very cold to religion during the post-revolutionary world, because of their bad experiences with the state Church of England--much like the experience today amongst European nations with state churches with very low church attendance. As such, to make a direct comparison between the religious controversies of today and the religious controversies of then would be sloppy.
It would perhaps be better to compare our situation to nations around the world today with little to no separation of church and state, like much of the Middle East, Sudan, Nigeria, and even Northern Ireland, to a small degree. Most of these nations are either full of extremists or paralyzed by sectarian violence.
Nations like Spain, Portugal, Ireland, and the Canadian province of Québec, in the mid-20th century, were heavily "Christian" states, much like many fundamentalist Christians today wish they could have here in the United States. Nevertheless, these states were often repressive to dissenting ideas, and decades later, the people of these countries generally want little to do with Christianity today. Québec, in particular, is known for many beautiful churches--which few attend today.
In short, our Founding Fathers were not gods, and they would likely balk today if we'd ask, "What Would George Do?" And regardless of what they believed, whether they were agnostic deists or devout Christians, they should not set the standard for what we would do today. However, we can learn from history and contemporary events to know that turning the United States into a "Christian country" would be a disastrous idea that would be a ticket to repression and an eventual mass rejection of Christianity in future generations.
America's genius has generally been with its diversity, where people have been historically judged by the validity of their ideas, rather than the ethnicity or religion of the person saying it. We're certainly not perfect, as a nation, but we're certainly better than many of the alternatives, and I hope people of all stripes stop to think of that.