It's pretty well known that Rick Santorum is an ardent supporter of teaching creationism in schools. The argument that creationists like Santorum often use is that evolution is just a theory. And since it is just a theory, it's clearly utterly and completely fallible, and alternate theories like intelligent design are just as reasonable and should clearly be presented side by side.
In reality, of course, this is a massive misunderstanding of how science works. Let's review with the very basics of science: there are events or facts that occur. Then science attempts to explain why those things occur. That is called a theory.
If I pick up an apple and drop it on the ground, what fact just happened? The fact that happened is that I picked up an apple and dropped it on the ground. Gravity is the theory that explains why the apple to fell to the ground. Just because gravity is a theory, should we teach some faith based theory, something like angels constantly blow on the Earth to hold everything down to it?
Or should we stop distinctively teaching germ theory because it is just a theory, and also teach in our public schools that people may get sick because the humors have turned against them? The "it's just a theory" argument that creationists use to try to discredit evolution is utter silliness. And for the funniest moment in the history of laying the smack down on creationists, check number 7 on this Cracked.com list.