Here is what was meant by Establishment

http://www.washingtonpost.com/wp-dyn/content/article/2006/06/27/AR2006062700539.html

Perhaps the most mis-used, misrepresented, abused, misinterpreted clause of the Constitution has to do with religion. While the Constitution NEVER states the famed "Separation of Church and State" line (that actually came about in the Thomas Jefferson letters and even there did not mean what it has come to mean), it does prohibit the establishment of a state religion.
Contextually, the collective memory of the Founding Fathers included the religious wars as Europe tried to escape the evil, cloying, clawing grasp of the pope, the religious wars that saw Lutherans and Calvinists and the Church of England and still others become THE state church...you had no choice, you WERE the religiou tied to the state.
No, the Founding Fathers were not trying to separate religion from public life. In fact, prayer was a regular portion of their meetings when putting together the Constitution and the Bill of Rights in which they sought the guidance of God. This is a far cry from the modern interpretation which seeks to expunge from public life prayer, religious references, religious morals.
The type of thing they sought to prevent was something like Somalia is about to endure. Make no mistake, when Sharia is invoked, civil and human rights go out the window. For all the cries to the contrary, Bible believers have done more to advance the cause of equality for women than any other group. Look where the Bible has gone, then look where it has not. Watch in Somalia, mark my words, some woman will be executed for violating Sharia through not wearing a veil or becoming educated or something similar. Everywhere Sharia is invoked, that happens.
"One of the pillars of our charter says any rule and law against the Islamic sharia law is null and void. We don't see it as a problem," government spokesman Abdirahman Dinari said."
This is what the clause preventing the establishment of a specific religion was designed to prevent. The State cannot compel you to be or not to be Catholic, Mormon, Presbyterian, non-denominational, Baptist, etc. The pope cannot rule here. The head of the Church of England has no power.
That is why this country remains great. Though we have drifted far from our roots, still, in comparison to most of the world, we have more freedom, more rights, more privileges, and more opportunities than anywhere else in the world. Grieve for Somalia...the establishment of Sharia is one of the greatest tragedies of the last decade.