The Heritage Argument for the 10 Commandments

I have been disturbed by the arguments for the display of the Ten Commandments on government property for a while now, but it wasn't until I woke up this morning that I realized what exactly my objection is. Supporters usually claim that the 10C deserve to be displayed because they are 1)part of our heritage and 2)what 80%-90% of citizens believe. 2) is clearly ridiculous: America was founded as a secular, inclusive nation, opposed to both the theocratic and French Revolutionary models. Even if 98% of citizens believe x, x is neither more valid nor supposed to be written into law. This is where 1) comes in. If the 10C are part of our heritage, then it adds weight to claim 2). However, 1) is misleading: it is a content-free claim, while the problem is the content. Let's assume that the claim that the Bible was a critically important document in the founding of America. It is at least theoretically possible that another book could have been the foundation of America. The pro-10C people would not support the display of the Koran or the works of Spinoza if either turned out to be the "founding book" of America. In this hypothetical, I imagine that they would still support the display of the 10C. The reason for the display of the 10C is not heritage. I strongly believe that the heritage claim should only be applied to documents that were clearly instrumental in our nation's founding: The Declaration of Independence and the Constitution. If the Declaration of Independence turned out to be a hoax, and we found the real DoI, then the real document would be deserving of the heritage status. The heritage claims of the DoI are content-independent, and thus valid. We should not display the 10C; we should display the DoI: it is part of our heritage.