The issue (for me) isn't what would carry the day in court, but what makes sense given world history regarding the influence of religious belief on government. I think history shows that far more often than not such influence is negative.
I realize this isn't what you are debating -- however, I'm an engineer, not a lawyer. My interest is not in the legal basis for the intent of the establishment clause: What is smart and what is legal are two different questions.
The founders set up a form of government unseen in the world at that time. They invented it out of whole-cloth based on their personal experience, and their view of the larger world. Their personal writing and beliefs are extremely relevant to a discussion since they formed the very basis of the government they invented! Central to their belief system is the belief that religious influence on government was something to be avoided at all costs. Again, I point to a myriad of letters from Jefferson, Franklin , Washington, Madison , etc. etc. These beliefs are the very foundation of the "Godless Constitution". To simply dismiss them because they are not admissible in a court of law completely misses the wisdom in the creation of our system of government and laws in the first place!
As to the legal battles surrounding religion and government we need not look very deep to find the roots of the controversy. How many Supreme Court justices self-identify as "Christian" … All of them.
Hence the crux of the (legal) debate: how can you expect a person, who acknowledges that they hold beliefs in revealed, absolute truth that are neither founded on demonstrable facts or evidence accountable to a law made by men? We can't – and that's why we have people like Scalia on the court who actually believe the Ten Commandments form part of the basis of our laws and "scholarly debate" on the subject (again, refer to Jefferson's writing on this subject where he coolly dismantled the argument that the Ten Commandments form the basis of common law: British common law, on which much American law was based, existed before Christianity had arrived in England.). [My aside: which Ten Commandments should we display anyway? Those in Exodus 30 or 34… they are VERY different yet the chapter 34 says they are the same as those Moses supposedly brought down from the mountain. I prefer the later ref in which we find 10- Thou Shalt Not Seethe a Kid in it's Mother's Milk.)
Could Abraham Lincoln, who wrote a manuscript arguing against the divinity of Christ and the divine inspiration of the Bible and stated:
"My earlier views of the unsoundness of the Christian scheme of salvation and the human origin of the scriptures, have become clearer and stronger with advancing years and I see no reason for thinking I shall ever change them."
be elected to office today? Of course not…This leads back to my original point: 'coming out Christian doesn't take ANY moral courage. It is akin to identifying as a republican while sitting in front of Tom Delay's Congress.
The mad-men have the keys to the kingdom.
As to Christianity itself, I doubt there would be many who professed to be Christian if they actually read the entire bible: and spent a bit of time really digesting what it says. I find it paints a picture of an ugly, vindictive god who would do such things as torment a good person (such as Job) simply to make a point to 'satan' (so god makes good people suffer so he can prove a point to the devil? Seems awfully vain to a rational person). It includes specific instructions on how and when to sell your children into sexual slavery… decrees to slaughter entire cities except for the virgins which were to be taken as spoils… the list goes on.
I do not doubt your intelligence, but I cannot understand how anyone who has put an effort into studying the foundations of the Christian belief system ( i.e. – the bible) could profess faith in such barbarism. And to deny the wisdom of the most brilliant people of an age (the founders) because their codification of that wisdom (separation of church and state) is legally debatable misses the larger lesson of history – which this country is well on it's way to repeating.