Freedom of Which Religion?

Our Constitution was made only for a moral and religious people. It is wholly inadequate to the government of any other.

John Adams

When the First Amendment was drafted, the United States was almost exclusively Christian.  Many of the states had an established religion and religious tests to hold office.  New England was established by a persecuted religious group who fled England two centuries before: The Puritans.  Pennsylvania was founded by a Quaker.  Virginia was Anglican.  The Scotch-Irish of the Carolinas were Presbyterians.  The Founders were aware of the diversity - being themselves members of the various denominations of Christianity - and also knew of the catastrophic wars that had torn through Europe.  In fact, Europe still had state-established religions.  The First Amendment addressed that directly, offering a live and let live solution to the frequent hostility among the various flavors of Christianity.  However, they never considered Hinduism, Islam, Voodoo, Satanism, or various other faiths.  Why would they?  And that was an oversight.

Islam is not compatible with the US Constitution.  If a majority of the citizens of the United States were to become Muslim, the Constitution would necessarily be discarded as against the Koran and failing to adhere to Sharia.  Remember, when the First Amendment was adopted, Islam and Christianity had been at war for more than a thousand years.  Islam was anathema to Western Civilization.  Why would anyone think that Islam would be openly integrated into a Western nation via an 18th Century amendment written for the governing of a universally Christian country?

Obviously, the history here is irrelevant.  The Supreme Court will not limit what religions are covered by the Freedom of Religion clause.  Well, maybe Pastafarianism.  The Founding Fathers did not foresee a time when uncontrolled migration would change the religious landscape.  Case in point, the huge influx of Catholics in the 19th Century was tumultuous because the US was a Protestant country.  This saw the rise of Nativism, which was an anti-Catholic movement in the mid-19th Century, most notably against the Irish.  Why would a different version of Christianity be such a problem?  Because they held allegiance to a foreign prince: the Pope.  As late as JFK - the first Catholic president - there were concerns that the Pope would determine US policies from Rome.

Western Civilization is dependent upon Christianity.  It is one of the primary foundations.  If it goes, so goes Western Civilization.  The West needs to prevent incompatible belief systems from taking hold.  It may be too late for some Western nations.