Also, The reference to the Constitution I believe refers only to the Federal government. State governments have their own constitutions.
Sorry, Pat, but both precedent and constitutional text would find fault in your stated position.
Regarding Louisiana's Ten Commandments law, as it is worded it will probably fail on "separation of church and state" rules. In the past, a similar or identical law was passed in several southern states and in each case was found to be unconstitutional. For one example, from 1980,
Stone v. Graham, case in which the U.S. Supreme Court on November 17, 1980, ruled (5–4) that a Kentucky statute requiring school officials to post a copy of the Ten Commandments (purchased with private contributions) on a wall in every public classroom violated the First Amendment’s establishment
www.britannica.com
Kentucky lost that one. I remember others that faded out in appellate courts after Stone vs. Graham set the standard and precedent.
As to state governments having their own constitutions, true but irrelevant. There is a clause in the U.S. Constitution that says its admonitions apply EVERYWHERE. See article 6, 2nd paragraph.
This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.
That "anything...to the contrary notwithstanding" is one of those legal "nuclear deterrent" clauses that is supposed to be a hard barrier.
I'm not a lawyer but I was around when these cases were in the news. If I recall the discussions correctly, ONE of the major flaws is the failure to post the central principles of other religions - i.e. the Analects of Confucius, the Koran, the Bhagavad Gita, and I'm sure I've left out a couple. Another major issue was that the commandments were deemed permissible ONLY in the context of a history class that covered the other types of scripture, i.e. a comparative religion class... OR the contributions of each of those holy books to our culture as an advanced historical class on factors in the development of our government.