riVeRraT, thanks for the clarification.
I should clarify a statement I made previously - while Constitutional rights in the U.S. aren't subject to the will of the majority of the people directly, per se, a sufficiently bigoted and malevolent majority can get together and amend the Constitution to deprive the minority of equal freedoms and rights.
I used the Texas example because it points to a further problem - even when the courts correct violations of the Constitution, if the other branches of government are led by those who ignore the law when it suits them, the violation of rights continues.
In partial response to Bob's question, Texas' constitution has been revised several times since Murray v. Hill for various reasons, including in response to lawsuits and obsolete portions. I suspect some of those dragging their heels would coyly claim that the requirement isn't strictly enforced anymore, so no harm, no foul. Many others probably would simply cloak themselves in their religion, rant about "activist judges", and portray disregard for the court decision as a virtue.
But the requirement is in the Texas Constitution, so it's the law, and it violates the U.S. Constitution. Nothing in that section of the Texas Constitution (or any other section, IIRC) states that clause is null and void, so the violation remains.
As for National v. State imposition of religion, many of the original colonies had established religions. The Constitution initially constrained the Federal government - and powers not in the purview of the Federal government fell to the states and/or citizens (10th Amendment), as you learned, but subsequent disestablishment of religion by state governments followed, and further amendment to the U.S. Constitution (14th) after the Civil War codified the extension of U.S. Constitutional rights to the citizens, particularly Section 1:
Section 1. All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside. No state shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any state deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.