Changing Interpretation, Unchanging Morals?

Many people have commented so far on how the separation of “church and state”, or the so called separation of legality and religion, seems to be a basic underlying principle of the legal system, and yet that the lines between the two are often blurred, allowing some religion to seep into law. This has been exemplified often in the history of the First Amendment of the Constitution and the various Supreme Court cases which bring into question the ‘Freedom of Religion’ Clause within said Amendment. These cases often bring into question the controversy that exists between the Establishment Cause and the Freedom to Act, clause. One promises that Congress will make no law impeding on a person’s right to practice their religion, while the other claims that the government will refuse to officially promote or fund any established religion. Both are very much a part of how the government was founded and run, and yet both seem to be in a constant clash with one another. That means that in these cases that come to the attention of the court, both standards must be taken into consideration, and therefore, the law will always be interpreted as best to the facts as possible. I believe this indicates that the law must be changing, as the interpretations of the law, buy the very nature of the First Amendment, have to change, as both the Establishment Clause and Freedom to Act Clause cannot both entirely be satisfied. So, with these changing interpretation of religion within the law, can it be said that moral remain unchanged, as in Traditional Natural Law?