The "Establishment Clause" constraint is clearly placed upon Congress, not the states. In fact, any law made by Congress constraining the states with respect to religion would be in direct violation of this amendment and therefore null and void.
"I think what we heard today echoed of George Wallace," Cohen said. "He said the federal courts have no authority to order him to do anything Alabama law doesn't require him to do. Whatever views Moore has about this, federal law is supreme."
This echoes of Reconstruction and violation of state sovereignty by the federal government. Unless (and even if) Cohen wishes to make some lame application of the "elastic interstate commerce clause", his claim that "federal law is supreme" in this case is unfounded. Federal law is NOT supreme where the federal government does not have jurisdiction.
Chief Justice Moore is right, and Mr. Cohen is dead wrong. The U.S. Constitution specifically and clearly excludes the federal government from jurisdiction over matters of religion, whether pro or con. By contrast, according to Chief Justice Moore, the Alabama State Constitution has no such prohibitions.
According to this article, the cause for action given by the Southern Poverty Law Center, Americans United for Separation of Church and State and the American Civil Liberties Union is that "the monument violated the constitution". What constitution are they referring to? This case, and others like it, should be non-starters.
While I don't personally advocate the incorporation of religion or religious documents into government at any level, I must acknowledge the U.S. Constitution and the primary importance of protecting it above all else. I am sworn to do so.
In Fact several of the states had "State Religions" when the constitution was ratified. I don't remember which, but apparently they all dropped them voluntairly.