"I am the Lord your God" isn't a source of U.S. law

I'm trying to put together a good legal post prior to the Supreme Court hearings on the related cases of the 10 Commandments in-between the Texas state legislature and the Texas Supreme Court, and the copies of the 10 Commandments on the walls in two Kentucky court houses. But I haven't gotten around to reading the lower court opinions yet, and I haven't had a class in law school yet which would really prepare me to comment on the Supreme Court's Establishment clause jurisprudence.

But one funny bit, from the Texas Attorney General's Op-Ed in the Houston Chronicle:
Among those commemorations is a replica of the Ten Commandments. The six-foot, red granite marker was donated in 1961 "to the youth and people of Texas" as a way to combat juvenile delinquency and promote a personal code of conduct for youth. In that spirit, the Legislature accepted the monument and placed it halfway between the Capitol and the State Supreme Court building, signifying the secular impact the Ten Commandments have had on the state's legal institutions.

What's funny about that, you ask? The word secular. It's funny because it does all the work in the argument. If you want to write an unbiased piece (and I would also say a credible piece), you don't modify the word impact with anything, and the paragraph doesn't lose it's ability to communicate. If you're arguing the other side, you can take the same paragraph and replace "secular" with "spiritual" or "religious." Those words fit the preceding sentences just as well. Now, the Attorney General is on one side of the case, so maybe asking for him to be unbiased isn't reasonable. But really the problem I have is that he's only writing a piece designed to persuade someone who thinks he's right. I'm far more interested in an article written to persuade me. More on this topic later after I've brushed up on it.