At the Republican debates, a reporter asked "Is there anybody on the stage that does not agree, believe in evolution?" Only three candidates raised their hand: Sam Brownback, Mike Huckabee, and Tom Tancredo.
It seems like a silly question at first - why should you even ask a President whether they believe in evolution? But it turns out that a lot of the policies of setting national law do tie back to this very simple question.
Pro-life vs. Pro-choice: If a supreme being created us, then we alone are not responsible for our lives. We have to assume that fiddling with His procreative process is a blasphemy against His creation. But if we're nothing but evolved monkeys, then we have no concern for aborting a fetus beyond our own respect for human life.
Stem cell research: If we presume that there is a God, then tampering with the building blocks of life is "playing God" and a perceived sin. If we are all just evolved by accident, then utilizing our science to extend and enhance human life is not just a right, but a duty to the success of our species.
Environmentalism: This could go either way, surprisingly. We could either assume that a supreme being could save us if we falter, or we could listen to the religious leaders who have pointed out that scripture commands us to take care of the Earth. On the evolutionary side, we could either declare that the management of the planet is up to us, or we could just resign ourselves to saying, "Well, survival of the fittest!" If we make ourselves extinct, then we weren't fit.
Foreign policy: Looking toward the Middle East, we can see that some countries allow their religious views to taint their foreign policy. Now, do we take a religious stance in response, and conquer the rest of the world in the name of the Lord, or do we take the non-religious stance and brush aside all holy wars as superstitious nonsense?
Of course, these are just examples; there are many other possible points of view which can stem from either stance. But the voting public seems to prefer a religious leader, or at least one who is a faith-holding Christian. John McCain gave the most creative response: He said that he believes in evolution, but cannot deny existence of a God when viewing the beauty of nature.
This is actually a common stance: a small but stable percentage of voters take an agnostic stance: all scientific findings so far point to evolution as a fact, but this does not mean that God could not have set up the laws of physics in the first place so that evolution would happen. An agnostic is not an atheist, contrary to common belief; an agnostic instead is one who neither denies nor confirms the existence of a supreme being, and perhaps believes that it isn't possible for us to know or is specifically not intended for us to know.
Nevertheless, we have not only never had an atheist president, we have never even had an agnostic one. Every single past President has professed some form of Christian faith. So it would seem, since all monotheistic Western religions assert that the Universe and life is intelligently designed, that anybody running for President had better be a faith-holder or risk losing votes.
The exception is a particular flavor of faith known as "Deism". Deists reject the idea that supernatural events such as prophecy and miracles are true, and they tend to assert that God does not interfere with human life and the laws of the universe. Well, there you go! There is a God, but the Universe came about from a Big Bang and life evolved anyway!
Who were the Deist Presidents? Nobody special - just Thomas Jefferson, James Madison, James Monroe, John Tyler, and Abraham Lincoln, that's all. Not to mention Benjamin Franklin. George Washington never affirmed Deism in his own life, but scholars after the fact state that he was.
Well, here's our founding fathers, all believing something that sounds awfully close to "evolution with a side of God". The thing is, scientists, and those who care greatly about the ever-increasing importance of science in our society, have a big, fat issue with sticking to a scripture account of nature and history. They want to be faithful, they would prefer to interpret scripture as a metaphor for the scientifically-proven events that happen, but the United States is pulling so hard to the religious right that it differs from a theocracy by now only by name. This represents a severe spin rightward from our origins.
At the very least, the next time John McCain is put on the spot about evolution, he would do well to simply answer that he is a Deist. With the good company that he's in, it couldn't hurt his voting base too much.