While I won't argue about there being no reference to God in the Consitution (I'm not saying there isn't, I just don't know and am not going to go look for it right now), there are plenty of references to God in the Declaration of Independence, which is the "charter" document of this nation, and thus a very important one when discussing whether the US was founded on Christian principles. 

Aside from this, there are numerous quotes from Founding Fathers stating that our republic can only stand so long as the people look to God. "[T]he only foundation for a useful education in a republic is to be aid in religion. Without this there can be no virtue, and without virtue there can be no liberty, and liberty is the object and life of all republican governments.  Without religion, I believe that learning does real mischief to the morals and principles of mankind." (Benjamin Rush, signer of the declaration). Gouverneur Morris, another signer, said "I believe that religion is the only solid base of morals and that morals are the only possible support of free governments. [T]herefore education should teach the precepts of religion and the duties of man towards God." And John Jay (first Chief Justice of the Supreme Court) said, "The Bible is the best of all books, for it is the word of God and teaches us the way to be happy in this world and in the next. Continue therefore to read it and to regulate your life by its precepts."

(http://www.free2pray.info/5founderquotes.html

But even if God wasn't mentioned in the Founding documents, the ideas expressed are still found in judeo-christian principals. The Founders established the government in such a way as to protect the people from the government (limiting the government as they did, ensuring that it could never get too much power) because they believed that rights were given not by man, nor by the government, but by God, aninherently Judeo-Christian principle (all men are created by God, thus, God gives them their rights, not man). John Adams wrote in a letter to Thomas Jefferson, "The general principles on which the fathers achieved independence were the general principles of Christianity. I will avow that I then believed, and now believe, that those general principles of Christianity are as eternal and immutable as the existence and attributes of God." 

The first ammendment was designed not to suggest that the founders had gotten nothing from religion, nor that they thought religion had no role in government, but to ensure that the government of the US did not make the same mistake as the governments of European countries (as well as others) had made in establishing a state religion (ex: England required it's people to be Anglican; for many years the French had to be Catholic) and thus overriding man's right to free will (another Christian concept).  

Wow, that was longer than I meant it to be...

You have to try looking at this from the other side of the spectrum, too. What if a parent sued because their kid was forced to write a report stating that molecules evolved into men over a period of billions of years? That definately involved a violation of their beleifs... I think what we see is atheism being defended but not Christianit.y.

And interesting that you should bring up the scopes trial. It used to be illegal to teach Evolution; now it is illegal to teach Creation! Or even both simultaneously!

In fact a teacher can lose their job for even suggesting that Intellegent Design is a possibility. Which is a flagrant violation of the standard of secularity they claim to be striving for. Here's why: Intellegent Design is an important tenet of every religion except for Athe.ism. If they are not allowing discussion of Intellegent Design into the classroom, than they are favoring Athe.ism over other religions, and that is a violation of the establishment clause.

"The Surpreme Judge of the world"...do you think they're referencing King George there? If you actually research the Constitution, you'll relaize they mention God throughout. They may not name Him by name, but that was because it was a respect issue, not a religious issue.

And fyi, the original pledge didn't even make mention to the specific flag. Just A flag.

Actually, this "wall between church and state" is nowhere to be found in the Constitution.  It's in a letter from Jefferson to the Danbury Baptist Association. The Constitution says that:

"Congress...shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof."-Amendment 1

and

"[N]o religious Test shall ever be required as a Qualification to any Office or public Trust under the United States." - Article 6

I think seperation of church and state is taken out of context way too often. If our founding fathers didn't want us to recognize God, they wouldn't have made him such a big deal. They wouldn't have left England to presue[sp?] religous freedom in the first place. That's the whole reason we're here.....

 Regardless, it is an interesting topic, and probably a difficult one to write about.