We often hear from people of all degrees of belief that the "US was founded on Judeo-Christian beliefs". You'll hear Sarah Palin and Michelle Bachman mention the writings of the founders. I've helped shape a law and you can find my writings. I would hardly suggest that that Construction Crane Bill is Atheist, Liberal, or Omnivorous. My opinions have no bearing on what the law passed was. We have the law, let's judge based on that rather than mining obscure quotes of little to no relevance.
The Constitution was adopted in 1789. The US Constitution at that time did not include any bills. They simply laid out how the government would work. So to say that the framers had some intent of religion behind the Separation of Powers laid out in Articles 1-7 is laughable. It's a clear statement of ignorance. Congress has the right to coin money. Congress has the right to establish a Post Office. How Spiritual!
So what are those making the claims talking about? Really, it's about the Bill of Rights. These aren't going to be much better for them. The Bill of Rights were formed in 1789 and introduced by James Madison. They were formed off of the writings of John Locke whom wasn't religious even by today's standards. In Letters Concerning Toleration his final point on keeping religion in society was, "Coercing religious uniformity would lead to more social disorder than allowing diversity." Source This is hardly the type of writing that leads to the support for a religiously based government. But I don't really want to fall into their mode of arguing quotes, so just know that the Bill of Rights was not written by the Founders in the Constitutional Convention. But there is another critical source for the Bill of Rights. The Virginia Declaration of Rights. These rights are all about equality. Article 2, "That all power is vested in, and consequently derived from, the people;" (Some may note that a "Creator" is noted in these rights. I would suggest that you read the whole of the text and see how much equality is listed in this text and ask how that squares up with the subjugation of women, Jesus calling a woman a dog, or the support of slavery in the Bible.) The writings of those signers of the Constitution simply aren't relevant because they aren't the authors of the Bill of Rights. Again, it would be like me saying because I vote for a law, it's now an Atheist Law.
Let's look at these Bill of Rights, especially in light of Judeo-Christian doctrine. The First Amendment calls for religious freedom. You can have any God. You can write about anything which would include criticism of religion. You can say anything about God. If we dig in the the J/C doctrine we find that the Ten Commandments were central. The first commandment is, Thou Shall Hath no other Gods before me. Odd. I'm going to base a set of laws on a religion and the first law violates said religion's first rule. Then we move on to the Second Amendment which is about the ability to defend yourself against a government. In Romans 13, Jesus himself says to submit to the authorities because no government exists without God's authority. Wow! The Second Amendment is against the teachings of the Bible as well? In fact, the entire list is about limiting the power of the government, which is contrary to what the Bible teaches. Consistently they are about submission to power. Sacrifice to Authority. The Bill of Rights in spirit is the opposite of that.
So what caused the founding of this country? Arguably, it was the taxation. a 1% tax as I understand it. So our ancestors had enough of the "heavy taxation". So what was Jesus's position on taxation? Matthew 21 finds Jesus saying "Render unto Cesar what is Cesar's.'" So even before the country was founded, Jesus and the attitude of the people was divided. Who could have guessed?
We could do this all day, but no one would read it. The facts are clear when you stop to look at them. The religion of the founders as we know it is a bunk argument. There is no religion in the original Constitution. If you see laws that are religious in the Bill of Rights, you should compare it to what is said in the Bible, and not what you imagine the Bible to say. This country is about standing up for yourself and limited government, while the Bible is about submission and the power of authorities. I don't see how the two go together.