Religion is powerful stuff. Historically religion is the tool employed by governments to control the people under their governance. This evolved over the past 500 years in the West, but is just beginning to take the same journey in the Middle East.

Consider - under the Holy Roman Empire legitimacy came from God and it was vested in the body of the Holy Roman Emperor. Charlamagne.

For 800 years a series of emperors and popes exercised control over the people of the empire, and controlled how people thought by demanding and enforcing a single system of religious thought.

Then Guttenberg invented his press, and as the government lost control on information they began to lose control over thought. Marten Luther was one who reasoably chafed at the interpretation of Christianity promoted and enforced by the Church, so he protested. Men with political concerns quickly saw the value of this Protestant ideology, and the wars of reformation began. Cast as Protestant vs. Catholic, that was really more Shirts vs. Skins as the have nots and oppressed took on the haves and oppressors.

The peace of Westphalia changed the rules. It established that Legitimacy came from the ability of a government/man to rise to power, and anyone who could take power could then pick the religion of his choice to exercise control over the people. This was in some ways a major change, as it broke up a broad system of control, but it really merely replaced it with many smaller systems of the exact same method of control.

The colonization of America took place in this era; and far from the direct control of Kings, thinking on governance evolved at a more rapid pace. Many of the original settlers came for religious freedom, but this was not freedom for all, but rather just freedom to make their own dogma the ruling dogma. The Puritans exercised the same single-minded control being exercised by Kings in Europe, and were at least as burtal in their methods. In many ways the Taliban of 2000 were little different than the Puritans of 1650.

But by the time of the American Revolution thought had evolved, guided by the theories of men like John Locke, to the radical new belief that legitimacy came from the people. But the only way to have legitimacy from the people was to disempower the abilty of the state to exercise idological control through a single state religion. And thus the Establishment Clause in the Bill of Rights. The Bill of Rights is a genius bit of revolutionary prevention. A state that cannot establish an ideology is a state far less able to oppress.

But all of this is about governance and human nature. Religion is a tool. If you can appreciate the idea that "guns don't kill, people do," then you can appreciate the idea that "religion does not oppress, governments do."

Bottom line is that the history books spin this in the wrong direction; and the modern luancy in America that interprets the Establishment Clause as meaning that governments cannot sponsor crosses on hilltops, or nativity scenes, or that public schools cannot play religious context music at Christmas completely misunderstands the purpose of the law.