The establishment clause of the U.S. Constitution, is derived from the opening lines of the first amendment which states "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof...  There are two ways that this statement is commonly misunderstood.  First it is often described as establishing a "wall of separation between Church and State."  In fact, those words are found nowhere in the constitution.  The phrase actually was coined later in a letter from Thomas Jefferson.        Second, and more importantly, it is assumed that if organized religion cannot be supported by the state, then secularism is somehow  "neutral."        Thus, by default, anything goes as long as it's "secular."                   Understanding the historical context is essential.           In the 18th century, an "established religion referred to an official State Church.  In the U.S., individual states had already established churches, such as the Anglican Church in Virginia.  The first amendment specifically applied to congress and prohibited a national church.  To prefer the Anglican Church over the congregationalists or Presbyterians would, at the time, mean alienating certain citizens and entire states.  States continued to have established churches well into the 19th century.    In addition, the First Amendment was not intended to prohibit religious activities in governmental institutions.  From the very beginning, Congress started each session with prayer.  That continues today and is led by an official chaplin.     Our Founding Fathers, particularly James Madison, believed that religious liberty was an innate right, and inseperable from the freedom of conscience. He also believed that religion would better flourish in a free marketplace of ideas.  That thinking is the basis for the free exercise clause.  This understanding of freedom of conscience is the foundation for other freedoms protected in the first amendment.  Without conscience rights, we cannot truly speak, write, assemble, or advocate freely from our deepest beliefs.  That's why the freedom of religion is often called "The first freedom."  Its position in the Bill of Rights highlights its importance.