In a monumental decision for the time (WWII had just ended, the posturing of the Cold War against communism was just beginning, many also feared the growing influence of catholicism and other "cults" in the country. The country's religious fervor was never higher. We added the motto "In God We Trust" to our currency in 1956 and "Under God" to the pledge of allegiance in 1954.), an 8-1 decision in favor of Mrs. McCollum set the precedent for all of the first amendment and fourteenth amendment Equal Protection Clause cases to follow.
Supreme Justice Black wrote, "The First Amendment rests upon the premise that both religion and government can best work to achieve their lofty aims if each is left free from the other in its respective sphere". This was the first time this amendment was ever tested, and in doing so, the justices relied heavily on the writings of James Madison and Thomas Jefferson to see how the founders intended the amendment to be interpreted.
In 1802, Thomas Jefferson wrote a letter to the Danbury Baptist Church in CT:
Believing with you that religion is a matter which lies solely between Man & his God, that he owes account to none other for his faith or his worship, that the legitimate powers of government reach actions only, & not opinions, I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should "make no law respecting an establishment of religion, or prohibiting the free exercise thereof", thus building a wall of separation between Church & State.
Both Jefferson and Madison had plenty to say on the matter. Please see the Intellects section above for links to many of their writings about the separation of church and state. The interesting part of this phrasing is that it really came from a devout protestant, Roger Williams of Rhode Island, back in 1644. In his "The Bloudy Tenent of Persecution, for Cause of Conscience", Williams intimates that religion mixed with government tends to corrupt religion (however, the opposite is also true) when he says:
"When they [the Church] have opened a gap in the hedge or wall of separation between the garden of the church and the wilderness of the world, God hath ever broke down the wall itself, removed the Candlestick, etc., and made His Garden a wilderness as it is this day. And that therefore if He will ever please to restore His garden and Paradise again, it must of necessity be walled in peculiarly unto Himself from the world, and all that be saved out of the world are to be transplanted out of the wilderness of the World."
Quite interesting how the foundation of the first amendment is based on the premise that religious belief needed to be protected from government affairs when now it is basically the other way around. Most of the first amendment cases now are in efforts to protect secular indifferent government from the deleterious effects of particular religious influence. And it all started with a brave woman named Vashti McCollum. The PBS documentary is really worth watching. I have tried to find the full version online but have only successfully found the trailer below. Please check with your PBS station or PBS online to find times to view the program.
PBS - The Lord is Not on Trial Here Today