There is much debate about what the First Amendment means, and what the Framers intended.
Some will take the words as fits their understanding and agenda, and will ignore the wishes of the Framers.
If the English language was as exact and unforgiving as an arithmetic formula, or a computer program where there are no alternatives for completing and executing a program except what is written in code, the the language and intent of the Framers of the Amendments to the Constitution would not have been the subject of debates by legal scholars for hundreds of years.
Is it right to follow the intent of the Framers (if that could be known) directly or indirectly, or is it right to apply the words of the Constitution and subsequent Amendments to modern day thought and the changing values of our society, and perhaps to support the whim of a particular group of people who feel their rights are abridged?
Does a rise in atheism mean that we should reshape the words and intent of the Framers because they don't like the words? Should we bend the words to fit our agendas, or should we make every effort to hold sacred those words and exhaust ourselves fully to rise to the level of the Framers? Who among us has demonstrated the level and depth of knowledge and understanding that the Founding Fathers did?
I firmly believe that the Framers would not find the current Pledge of Allegiance, which is optional and not mandatory, to be in violation of the establishment clause in the first Amendment were they suddenly transported into the present from the late 18th century.
If the Pledge were mandatory, which it isn't, that would be a different matter.
I do not view the Pledge as a prayer, an act or worship, or a ritual of religion, but rather a custom and personal choice which is but a manifested expression of nationalism.
I am providing a link below to a scholarly work on the "Intellectual Origins of the Establishment Clause."
I believe this article has value if we truly want to properly follow the wishes of the Framers, who valued the rights and freedoms of human beings, those rights granted by God (their words in nearly all of their writing and thought at that time) at the highest level. The central theme of the Establishment Clause was to protect the liberty of conscience from the coercive influence of government, an idea usually first and primarily attributed to the writings of John Locke.
Any action by Government that would abridge these rights of conscience, would be prohibited.
The central issue of Constitutionality of the Prayer has to do with the preservation of rights, as the Bill of Rights is just that, preservation of rights.
Someone may state their opinion that the pledge, including the phrase "under God" violates their rights, but I have yet to see what personal right the optionally recited Pledge violates.
The Supreme Court will likely focus most on what they believe the spirit of the Founders was when they ratified the establishment clause in the first amendment, and the spirit of that clause was supporting the right of liberty of conscience.
In those days, conscience was very lively in our Founders. That was a time when a man's word meant something, when morality meant something, when God was worshiped reverently by those who were of the Fundamentalist variety, or who favored Deism.
No one would argue that the Framers and Founding Fathers were not men of strong conscience and principle.
Additionally the article shows there were no atheists among the Framers as evidence by their writings and arguments.
These men believed in God of some variety, and believed that man was inherently free to practice his own beliefs without intervention by the Federal Government.
They held the truth to be self evident, that all men are created equally endowed by their Creator with the right of religious choice.
The Constitution protects that right, the right of conscience, and the optional recitation of the Pledge of Allegiance in no way abridges that right of religious freedom.
Those who eventually bring this case to the high court to remove the words "under God" will not be successful if the court adheres to the will of the Framers in my opinion.
Below is the link to the article mentioned above. It is in PDF format, and well worth the read to get a scholarly review of the evolution of the Establishment Clause up till the time of ratification.
Read the article objectively if possible, and attempt to place yourself back in those days, and then decide if the Pledge really does violate the spirit of First Amendment.
If nothing else, the article is a great lesson in a very important slice of American History, something that is most valuable to both American Citizens, and those who are not who continue to voice their opinion on this subject.
http://www.nyu.edu/pages/lawreview/77/2/feldman.pdf