What part do you think is untenable and unacceptable?
Thinkers far in advance of myself have commented eloquently on how only two things could be true of the Justices who wrote this opinion: either they were ignorant of history, or they wrote in deliberate intent to deceive.
However, I accept your invitation to take a stab at them.
Neither a state nor the Federal Government can set up a church.
That is fine.
Neither can pass laws which aid one religion, aid all religions, or prefer one religion over another.
Wrong, wrong, and wrong. Laws were passed during the period of the Articles of Confederation that called for general promotion of education and religion. No founder ever made a statement indicating that the state was to be neutral between religion and irreligion. Christianity was overwhelmingly the religion of Americans, still is. No founder ever decried the fact that there was a dominant religion. On something like choice of a holiday or display of a creche, there was, needless to say, a complete absence of Political Correctness. "Preferences", if you will, for Christianity abounded. This state of affairs is entirely consistent with the guarantee of freedom of conscious and banning of establishment in the sense that the founders understood it.
I'm going to stop there and take a breath.
The Founders, bless their hearts, did not always live up to the Constitution that they wrote. For example, the Alien and Sedition Acts were clearly unconstitutional under the 1st and 5th amendments but were nonetheless signed into law by John Adams. To give a closer example, Massachusetts had an established church (Congregationalist) until 1831, supported directly by the taxpayers. The deeds of the Founders do not make the basis for our laws, the Constitution does.
Christianity was overwhelmingly the religion of Americans, still is. No founder ever decried the fact that there was a dominant religion.
They certainly decried the presence of dominant sects. Then, as now, you cannot attend a "Christian" church. Every church is Anglican, Baptist, Congregationalist, Quaker, etc. Also,a key purpose of the Bill of Rights is protceting the rights of those who hold minority or unpopular beliefs. The fact that a majority of a community believe in one particular sect does not give them the right to tax everyone support it.
Getting back to the Everson, do you think government can prefer one religion to another in passing laws and policies? If a city council donates land for a Catholic Churce while turning down zoning for a Synagogue is that in accord with the Constitution? I'd say it is clearly unconstitutional. So would James Madison. Here is a veto message from his presidency:
February 28, 1811So even in the early days of the republic, politicians were trying to curry favor by supporting the locally popular religion and even then wiser minds realized that such practices were contrary to the Establishment Clause. Whether an acre or a square foot, the principle is the same.
To the House of Representatives of the United States:
Having examined and considered the bill entitled "An act for the relief of Richard Tervin, William Coleman, Edwin Lewis, Samuel Mims, Joseph Wilson, and the Baptist Church at Salem Meeting House, in the Mississippi Territory," I now return the same to the House of Representatives, in which it originated, with the following objection:Because the bill in reserving a certain parcel of land of the United States for the use of said Baptist Church comprises a principle and precedent for the appropriation of funds of the United States for the use and support of religious societies, contrary to the article of the Constitution which declares that "Congress shall make no law respecting a religious establishment."
These are fine.
No tax in any amount, large or small, can be levied to support any religious activities or institutions, whatever they may be called, or whatever form they may adopt to teach or practice religion.
Not fine. Do Federal and State governments stay well within the bounds of Article I Section 8? No. Since they do not, it is not feasible to maintain a Madisonian strictness here. There is a danger that government will hamper religious works. Hampering religion should be treated as a greater danger than aiding it.
Anywhere treasury funds are used to support private activities or institutions of any kind, the government should not discriminate against a religious organization which provides an equivalent.