I'm going to start with combining the "preamble" and the first two of the usual Ten Commandments. Remember, most of the time when you hear someone rattle these off, they get perhaps the first sentence.
And God spake all these words, saying,
I am the Lord thy God, which have brought thee out of the land of Egypt, out of the house of bondage.
1.Thou shalt have no other gods before me.
2.Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. Thou shalt not bow down thyself to them, nor serve them: for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me; And shewing mercy unto thousands of them that love me, and keep my commandments.
Now, really, the "preamble" is just establishing who is supposedly speaking - Yahweh, one of (eventually "the") Jewish gods, later the Judeo-Christian god. Yes, the Israelites were polytheists, worshiping not just YHWH, but (depending on tribe, as this was split between Northern and Southern kingdoms) El, Asherah (who was his wife - yes, god was married) and Ba'al, among others. And this was perfectly normal! All the stuff you read about being angry at a bull being created, about Beelzebub (which is a perversion of one of Ba'al's titles) and the like - guess what. It's ancient Israelite politics.
Don't take my word for it. Look it up. Use nonbiased (IE, not coming from "God's been this way always, let's find proof" - or 'christian' - sources.)
Still, we have an obvious and a not so obvious problem with these commandments and the US constitution and bill of rights.
The obvious one, of course, is the first amendment.
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
The God mentioned int he first two commandments says, quite frankly, I am the only god, you can have no others, you can't make idols to anything else and worship them. This command does two things:
- It establishes a sole religion - Yahwist, for lack of a better term (and because it's shorter than typing Judeo-Christian,) and
- It forbids the worship of anything else.
An argument, though rather tangent, could also be made that it goes against freedom of speech in its forbidding of making images of other things to worship, or for that matter questioning this deity in and of itself.
The other, less obvious conflict - and this is something that the bible contradicts itself in several times, but we're looking at these commandments as being "founding" documents, after all - is that of generational sin or generational guilt. Re-read this part:
for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me
Yes, this carries on the whole "everyone's a sinner" thanks to Adam and Eve and piles more on, carrying the father's guilt on for three or four generations. (Which begs the question, is the son of someone who doesn't believe or worships differently, who believes the same way, twice as guilty?)
Yet, article V:
No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation
"Sin" and "Crime" being roughly analogous (sin being defined as a "crime against god,) again we have conflict. This deity would hold four generations accountable - and let's not forget that "original sin." Meanwhile, article V has each person tried for their own crimes. (Due process is also reinforced in the Fourteenth amendment - which would, again, prevent someone from being held accountable for a crime they didn't commit - but as the Bill of Rights is only the first ten, I'm only bringing it up as a note here.)
So, two commandments down.
Secular nation, 2, Christian nation, 0.